Now Stable

"New on the Web": For a given set of browsers, what APIs became stable and when, ordered reverse chronologically.

It's a great source of information for posts like this

Example Comparisons
Browsers
Features

Stable APIs

Below is a list of features that are in Edge and Firefox, ordered reverse chronologically by when they became stable (i.e, available in the last browser).

2026/3

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Iterator.concat 📋Firefox1/13/2026 Edge3/12/202658

2026/2

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Map.getOrInsert 📋Firefox10/14/2025 Edge2/14/2026123
javascript.builtins.Map.getOrInsertComputed 📋Firefox10/14/2025 Edge2/14/2026123
javascript.builtins.WeakMap.getOrInsert 📋Firefox10/14/2025 Edge2/14/2026123
javascript.builtins.WeakMap.getOrInsertComputed 📋Firefox10/14/2025 Edge2/14/2026123

2026/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Date.toTemporalInstant 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.Duration 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.abs 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.blank 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.days 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.hours 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.microseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.milliseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.minutes 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.months 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.nanoseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.negated 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.round 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.seconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.sign 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.total 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.weeks 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Duration.years 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.epochMilliseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.epochNanoseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.fromEpochMilliseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.fromEpochNanoseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.round 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.toZonedDateTimeISO 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Instant.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.instant 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.plainDateISO 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.plainDateTimeISO 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.plainTimeISO 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.timeZoneId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.Now.zonedDateTimeISO 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.calendarId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.day 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.dayOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.dayOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.daysInMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.daysInWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.daysInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.era 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.eraYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.inLeapYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.month 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.monthCode 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.monthsInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toPlainDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toPlainMonthDay 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toPlainYearMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.toZonedDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.weekOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.withCalendar 📋Firefox5/27/2025 Edge1/21/2026239
Firefox: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.Firefox for Android: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.
javascript.builtins.Temporal.PlainDate.year 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDate.yearOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.calendarId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.day 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.dayOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.dayOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.daysInMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.daysInWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.daysInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.era 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.eraYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.hour 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.inLeapYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.microsecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.millisecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.minute 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.month 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.monthCode 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.monthsInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.nanosecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.round 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.second 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toPlainDate 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toPlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.toZonedDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.weekOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.withCalendar 📋Firefox5/27/2025 Edge1/21/2026239
Firefox: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.Firefox for Android: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.
javascript.builtins.Temporal.PlainDateTime.withPlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.year 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainDateTime.yearOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.calendarId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.day 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.monthCode 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.toPlainDate 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainMonthDay.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.PlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.hour 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.microsecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.millisecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.minute 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.nanosecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.round 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.second 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainTime.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.calendarId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.daysInMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.daysInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.era 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.eraYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.inLeapYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.month 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.monthCode 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.monthsInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.toPlainDate 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.PlainYearMonth.year 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.add 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.calendarId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.compare 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.day 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.dayOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.dayOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.daysInMonth 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.daysInWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.daysInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.epochMilliseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.epochNanoseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.equals 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.era 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.eraYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.from 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.getTimeZoneTransition 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.hour 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.hoursInDay 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.inLeapYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.microsecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.millisecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.minute 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.month 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.monthCode 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.monthsInYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.nanosecond 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.offset 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.offsetNanoseconds 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.round 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.second 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.since 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.startOfDay 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.subtract 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.timeZoneId 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toInstant 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toJSON 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toLocaleString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toPlainDate 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toPlainDateTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toPlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.toString 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.until 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.valueOf 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.weekOfYear 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.with 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.withCalendar 📋Firefox5/27/2025 Edge1/21/2026239
Firefox: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.Firefox for Android: Calendars islamic, islamic-rgsa and islamic-umalqura are not available. See bug 1950425 and bug 1954138.
javascript.builtins.Temporal.ZonedDateTime.withPlainTime 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.withTimeZone 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.year 📋Firefox5/27/2025 Edge1/21/2026239
javascript.builtins.Temporal.ZonedDateTime.yearOfWeek 📋Firefox5/27/2025 Edge1/21/2026239
javascript.statements.import.import_attributes.type_css Edge3/22/2024 Firefox1/13/2026662
javascript.statements.import.service_worker_support Edge5/27/2021 Firefox1/13/20261692

2025/12

API First Browser Date Last Browser Date Days Notes
javascript.builtins.FinalizationRegistry.register.symbol_as_target Edge1/12/2023 Firefox12/9/20251062
javascript.builtins.WeakMap.symbol_as_keys Edge1/12/2023 Firefox12/9/20251062
javascript.builtins.WeakRef.WeakRef.symbol_as_target Edge1/12/2023 Firefox12/9/20251062
javascript.builtins.WeakSet.symbol_as_keys Edge1/12/2023 Firefox12/9/20251062

2025/11

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Atomics.waitAsync 📋Edge4/15/2021 Firefox11/11/20251671
Chrome: The Atomics.waitAsync() method never times out. See bug 40742782.Chrome Android: The Atomics.waitAsync() method never times out. See bug 40742782.Edge: The Atomics.waitAsync() method never times out. See bug 40742782.Quest Browser: The Atomics.waitAsync() method never times out. See bug 40742782.Opera Android: The Atomics.waitAsync() method never times out. See bug 40742782.WebView Android: The Atomics.waitAsync() method never times out. See bug 40742782.

2025/9

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Uint8Array.fromBase64 📋Firefox11/26/2024 Edge9/5/2025283
javascript.builtins.Uint8Array.fromHex 📋Firefox11/26/2024 Edge9/5/2025283
javascript.builtins.Uint8Array.setFromBase64 📋Firefox11/26/2024 Edge9/5/2025283
javascript.builtins.Uint8Array.setFromHex 📋Firefox11/26/2024 Edge9/5/2025283
javascript.builtins.Uint8Array.toBase64 📋Firefox11/26/2024 Edge9/5/2025283
javascript.builtins.Uint8Array.toHex 📋Firefox11/26/2024 Edge9/5/2025283

2025/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.AsyncDisposableStack 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.@@asyncDispose 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.AsyncDisposableStack 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.adopt 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.defer 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.disposeAsync 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.disposed 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.move 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncDisposableStack.use 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.AsyncIterator.@@asyncDispose 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.@@dispose 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.DisposableStack 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.adopt 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.defer 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.dispose 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.disposed 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.move 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.DisposableStack.use 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.Iterator.@@dispose 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.SuppressedError 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.SuppressedError.SuppressedError 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.SuppressedError.error 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.SuppressedError.suppressed 📋Edge3/6/2025 Firefox7/22/2025138
javascript.builtins.Symbol.asyncDispose 📋Edge7/25/2024 Firefox7/22/2025362
Node.js: Only available for fs and stream resources.Node.js: Only available for fs and stream resources.
javascript.builtins.Symbol.dispose 📋Edge5/17/2024 Firefox7/22/2025431
Node.js: Only available for fs and stream resources.Node.js: Only available for fs and stream resources.
javascript.statements.await_using 📋Edge3/6/2025 Firefox7/22/2025138
javascript.statements.using 📋Edge3/6/2025 Firefox7/22/2025138

2025/5

API First Browser Date Last Browser Date Days Notes
javascript.builtins.RegExp.escape 📋Firefox1/7/2025 Edge5/1/2025114

2025/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Error.captureStackTrace 📋Edge1/15/2020 Firefox4/29/20251931
javascript.builtins.Error.isError 📋Edge3/6/2025 Firefox4/29/202554
Node.js: Returns false for DOMException instances. See issue 56497.Safari: Returns false for DOMException instances.Safari on iOS: Returns false for DOMException instances.WebView on iOS: Returns false for DOMException instances.
javascript.grammar.trailing_commas.trailing_commas_in_dynamic_import 📋Edge5/27/2021 Firefox4/29/20251433
Node.js: The second parameter no longer throws a parser error, but the --experimental-json-modules flag is still needed to load JSON modules.
javascript.operators.import.options_parameter 📋Edge5/27/2021 Firefox4/29/20251433
Node.js: The second parameter no longer throws a parser error, but the --experimental-json-modules flag is still needed to load JSON modules.
javascript.statements.import.import_attributes 📋Edge3/22/2024 Firefox4/29/2025403
javascript.statements.import.import_attributes.type_json Edge3/22/2024 Firefox4/29/2025403
javascript.builtins.DataView.getFloat16 📋Firefox8/6/2024 Edge4/4/2025241
javascript.builtins.DataView.setFloat16 📋Firefox8/6/2024 Edge4/4/2025241
javascript.builtins.Float16Array 📋Firefox8/6/2024 Edge4/4/2025241
javascript.builtins.Float16Array.Float16Array 📋Firefox8/6/2024 Edge4/4/2025241
javascript.builtins.Math.f16round 📋Firefox8/6/2024 Edge4/4/2025241
javascript.builtins.Atomics.pause 📋Edge2/6/2025 Firefox4/1/202554

2025/3

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DurationFormat 📋Edge9/19/2024 Firefox3/4/2025166
javascript.builtins.Intl.DurationFormat.DurationFormat 📋Edge9/19/2024 Firefox3/4/2025166
javascript.builtins.Intl.DurationFormat.format 📋Edge9/19/2024 Firefox3/4/2025166
javascript.builtins.Intl.DurationFormat.formatToParts 📋Edge9/19/2024 Firefox3/4/2025166
javascript.builtins.Intl.DurationFormat.resolvedOptions 📋Edge9/19/2024 Firefox3/4/2025166
javascript.builtins.Intl.DurationFormat.supportedLocalesOf 📋Edge9/19/2024 Firefox3/4/2025166

2025/2

API First Browser Date Last Browser Date Days Notes
javascript.builtins.JSON.isRawJSON 📋Edge6/2/2023 Firefox2/4/2025613
javascript.builtins.JSON.parse.reviver_parameter_context_argument 📋Edge6/2/2023 Firefox2/4/2025613
javascript.builtins.JSON.rawJSON 📋Edge6/2/2023 Firefox2/4/2025613

2025/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Promise.try 📋Edge8/22/2024 Firefox1/7/2025138

2024/10

API First Browser Date Last Browser Date Days Notes
javascript.regular_expressions.modifier 📋Edge5/17/2024 Firefox10/29/2024165
javascript.builtins.Iterator.Iterator 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.drop 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.every 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.filter 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.find 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.flatMap 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.forEach 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.from 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.map 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.reduce 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.some 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.take 📋Edge2/23/2024 Firefox10/1/2024221
javascript.builtins.Iterator.toArray 📋Edge2/23/2024 Firefox10/1/2024221

2024/8

API First Browser Date Last Browser Date Days Notes
javascript.regular_expressions.named_capturing_group.duplicate_named_capturing_groups Edge5/17/2024 Firefox8/6/202481

2024/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.ArrayBuffer.ArrayBuffer.maxByteLength_option 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.ArrayBuffer.maxByteLength 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.ArrayBuffer.resizable 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.ArrayBuffer.resize 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.SharedArrayBuffer.SharedArrayBuffer.maxByteLength_option 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.SharedArrayBuffer.grow 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.SharedArrayBuffer.growable 📋Edge3/13/2023 Firefox7/9/2024484
javascript.builtins.SharedArrayBuffer.maxByteLength 📋Edge3/13/2023 Firefox7/9/2024484

2024/6

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Set.difference 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.intersection 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.isDisjointFrom 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.isSubsetOf 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.isSupersetOf 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.symmetricDifference 📋Edge2/23/2024 Firefox6/11/2024109
javascript.builtins.Set.union 📋Edge2/23/2024 Firefox6/11/2024109

2024/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.Segmenter 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segmenter.Segmenter 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segmenter.resolvedOptions 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segmenter.segment 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segmenter.supportedLocalesOf 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segments 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segments.@@iterator 📋Edge11/19/2020 Firefox4/16/20241244
javascript.builtins.Intl.Segments.containing 📋Edge11/19/2020 Firefox4/16/20241244

2024/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.fromAsync 📋Firefox7/4/2023 Edge1/25/2024205
javascript.builtins.ArrayBuffer.detached 📋Edge6/2/2023 Firefox1/23/2024235
javascript.builtins.ArrayBuffer.transfer 📋Edge6/2/2023 Firefox1/23/2024235
javascript.builtins.ArrayBuffer.transferToFixedLength 📋Edge6/2/2023 Firefox1/23/2024235

2023/12

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Promise.withResolvers 📋Edge11/2/2023 Firefox12/19/202347

2023/10

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Map.groupBy 📋Edge9/15/2023 Firefox10/24/202339
javascript.builtins.Object.groupBy 📋Edge9/15/2023 Firefox10/24/202339
javascript.builtins.String.isWellFormed 📋Edge3/13/2023 Firefox10/24/2023225
javascript.builtins.String.toWellFormed 📋Edge3/13/2023 Firefox10/24/2023225

2023/9

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter.options_roundingMode_parameter Firefox8/1/2023 Edge9/15/202345

2023/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingIncrement_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingMode_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingPriority_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_signDisplay_parameter.negative Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_trailingZeroDisplay_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_useGrouping_parameter.string_values Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.format.number_parameter-string_decimal Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.formatRange 📋Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.NumberFormat.formatRangeToParts 📋Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter.options_roundingPriority_parameter Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.Intl.PluralRules.selectRange 📋Edge10/3/2022 Firefox8/1/2023302
javascript.builtins.RegExp.unicodeSets 📋Edge4/6/2023 Firefox8/1/2023117

2023/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.toReversed 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.Array.toSorted 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.Array.toSpliced 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.Array.with 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.TypedArray.toReversed 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.TypedArray.toSorted 📋Edge2/9/2023 Firefox7/4/2023145
javascript.builtins.TypedArray.with 📋Edge2/9/2023 Firefox7/4/2023145

2023/6

API First Browser Date Last Browser Date Days Notes
javascript.operators.import.worker_support Edge2/7/2020 Firefox6/6/20231215
javascript.statements.import.worker_support Edge2/7/2020 Firefox6/6/20231215

2022/10

API First Browser Date Last Browser Date Days Notes
javascript.operators.import_meta.resolve 📋Edge9/1/2022 Firefox10/18/202247
Node.js: Returns a URL object instead of a string.

2022/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.findLast 📋Edge1/6/2022 Firefox8/23/2022229
javascript.builtins.Array.findLastIndex 📋Edge1/6/2022 Firefox8/23/2022229
javascript.builtins.TypedArray.findLast 📋Edge1/6/2022 Firefox8/23/2022229
javascript.builtins.TypedArray.findLastIndex 📋Edge1/6/2022 Firefox8/23/2022229

2022/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.AggregateError.serializable_object Edge2/3/2022 Firefox7/26/2022173
Chrome: AggregateError serializes to the Error type, without additional properties.Chrome Android: AggregateError serializes to the Error type, without additional properties.Edge: AggregateError serializes to the Error type, without additional properties.Firefox: AggregateError serializes to the AggregateError type, with properties name, message, cause, and errors.Firefox for Android: AggregateError serializes to the AggregateError type, with properties name, message, cause, and errors.Quest Browser: AggregateError serializes to the Error type, without additional properties.Opera: AggregateError serializes to the Error type, without additional properties.Opera Android: AggregateError serializes to the Error type, without additional properties.Samsung Internet: AggregateError serializes to the Error type, without additional properties.WebView Android: AggregateError serializes to the Error type, without additional properties.
javascript.builtins.Error.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serialized properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 adds serialization of stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 adds serialization of stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serialized properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 adds serialization of stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 adds serialization of stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.EvalError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.RangeError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.ReferenceError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.SyntaxError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.TypeError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).
javascript.builtins.URIError.serializable_object 📋Edge1/15/2020 Firefox7/26/2022923
Firefox: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).Firefox for Android: Version 103 serializable properties: name, message, cause, fileName, lineNumber and columnNumber.Firefox for Android: Version 104 also serializes stack in the main thread (window.postMessage() and structuredClone()).Firefox for Android: Version 110 also serializes stack in workers (worker.postMessage() and structuredClone()).

2022/3

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.supportedValuesOf 📋Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_calendar Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_collation Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_currency Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_numberingSystem Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_timeZone Firefox10/5/2021 Edge3/3/2022149
javascript.builtins.Intl.supportedValuesOf.key_parameter_unit Firefox10/5/2021 Edge3/3/2022149

2021/10

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZoneName_parameter.extended_values Firefox8/10/2021 Edge10/21/202172
javascript.classes.static.initialization_blocks 📋Edge9/24/2021 Firefox10/5/202111

2021/9

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Object.hasOwn 📋Edge9/2/2021 Firefox9/7/20215
javascript.builtins.Error.Error.options_cause_parameter 📋Firefox8/10/2021 Edge9/2/202123
javascript.builtins.Error.cause 📋Firefox8/10/2021 Edge9/2/202123
Chrome: Before version 125, default console logging for Error objects does not print the cause.Chrome Android: Before version 125, default console logging for Error objects does not print the cause.Edge: Before version 125, default console logging for Error objects does not print the cause.Quest Browser: Before version false, default console logging for Error objects does not print the cause.Opera: Before version 111, default console logging for Error objects does not print the cause.Opera Android: Before version 83, default console logging for Error objects does not print the cause.Safari: Default console logging for Error objects does not print the cause.Safari on iOS: Default console logging for Error objects does not print the cause.Samsung Internet: Before version 27.0, default console logging for Error objects does not print the cause.WebView Android: Before version 125, default console logging for Error objects does not print the cause.WebView on iOS: Default console logging for Error objects does not print the cause.

2021/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.formatRange 📋Edge1/15/2020 Firefox8/10/2021573
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.
javascript.builtins.Intl.DateTimeFormat.formatRangeToParts 📋Edge1/15/2020 Firefox8/10/2021573
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.

2021/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.at 📋Firefox7/13/2021 Edge7/22/20219
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_dayPeriod_parameter Firefox7/13/2021 Edge7/22/20219
javascript.builtins.String.at 📋Firefox7/13/2021 Edge7/22/20219
javascript.builtins.TypedArray.at 📋Firefox7/13/2021 Edge7/22/20219
javascript.classes.private_class_fields 📋Edge1/15/2020 Firefox7/13/2021545
javascript.classes.private_class_fields_in 📋Edge5/27/2021 Firefox7/13/202147
javascript.classes.private_class_methods 📋Edge7/16/2020 Firefox7/13/2021362

2021/6

API First Browser Date Last Browser Date Days Notes
javascript.operators.await.top_level 📋Edge3/4/2021 Firefox6/1/202189
Node.js: Not supported in CommonJS modules.Safari: Doesn't support multiple modules simultaneously importing a module containing a top-level await (see bug 242740).Safari on iOS: Doesn't support multiple modules simultaneously importing a module containing a top-level await (see bug 242740).WebView on iOS: Doesn't support multiple modules simultaneously importing a module containing a top-level await (see bug 242740).

2021/5

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.IntlLegacyConstructedSymbol 📋Firefox6/13/2017 Edge5/27/20211444
Chrome: The fallback symbol property has description IntlFallback.Chrome Android: The fallback symbol property has description IntlFallback.Edge: The fallback symbol property has description IntlFallback.Node.js: The fallback symbol property has description IntlFallback.Quest Browser: The fallback symbol property has description IntlFallback.Opera: The fallback symbol property has description IntlFallback.Opera Android: The fallback symbol property has description IntlFallback.Samsung Internet: The fallback symbol property has description IntlFallback.WebView Android: The fallback symbol property has description IntlFallback.
javascript.builtins.Intl.NumberFormat.NumberFormat.IntlLegacyConstructedSymbol 📋Firefox6/13/2017 Edge5/27/20211444
Chrome: The fallback symbol property has description IntlFallback.Chrome Android: The fallback symbol property has description IntlFallback.Edge: The fallback symbol property has description IntlFallback.Node.js: The fallback symbol property has description IntlFallback.Quest Browser: The fallback symbol property has description IntlFallback.Opera: The fallback symbol property has description IntlFallback.Opera Android: The fallback symbol property has description IntlFallback.Samsung Internet: The fallback symbol property has description IntlFallback.WebView Android: The fallback symbol property has description IntlFallback.

2021/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.RegExp.hasIndices 📋Edge4/15/2021 Firefox4/19/20214

2021/3

API First Browser Date Last Browser Date Days Notes
javascript.statements.export.arbitrary_module_namespace_identifier_names Edge1/21/2021 Firefox3/23/202161
javascript.statements.import.arbitrary_module_namespace_identifier_names Edge1/21/2021 Firefox3/23/202161

2021/2

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DisplayNames 📋Edge4/13/2020 Firefox2/23/2021316
javascript.builtins.Intl.DisplayNames.DisplayNames 📋Edge4/13/2020 Firefox2/23/2021316
javascript.builtins.Intl.DisplayNames.of 📋Edge4/13/2020 Firefox2/23/2021316
javascript.builtins.Intl.DisplayNames.resolvedOptions 📋Edge4/13/2020 Firefox2/23/2021316
javascript.builtins.Intl.DisplayNames.supportedLocalesOf 📋Edge4/13/2020 Firefox2/23/2021316

2021/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.Collator.Collator.options_collation_parameter Edge10/9/2020 Firefox1/26/2021109

2020/12

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_fractionalSecondDigits_parameter Edge7/16/2020 Firefox12/15/2020152

2020/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.AggregateError 📋Firefox7/28/2020 Edge8/27/202030
javascript.builtins.AggregateError.AggregateError 📋Firefox7/28/2020 Edge8/27/202030
javascript.builtins.AggregateError.errors 📋Firefox7/28/2020 Edge8/27/202030
javascript.builtins.Promise.any 📋Firefox7/28/2020 Edge8/27/202030
javascript.builtins.String.replaceAll 📋Firefox6/2/2020 Edge8/27/202086
javascript.operators.logical_and_assignment 📋Firefox7/28/2020 Edge8/27/202030
javascript.operators.logical_or_assignment 📋Firefox7/28/2020 Edge8/27/202030
javascript.operators.nullish_coalescing_assignment 📋Firefox7/28/2020 Edge8/27/202030
javascript.statements.export.namespace 📋Edge1/15/2020 Firefox8/25/2020223
Node.js: Modules must either have a filename ending in .mjs, or the nearest parent package.json file must contain "type": "module". See Node's ECMAScript Modules documentation for more details.

2020/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.DataView.DataView.sharedarraybuffer_support Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.FinalizationRegistry 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.FinalizationRegistry.FinalizationRegistry 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.FinalizationRegistry.register 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.FinalizationRegistry.unregister 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_dateStyle_parameter Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeStyle_parameter Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.SharedArrayBuffer 📋Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.SharedArrayBuffer.@@species 📋Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.SharedArrayBuffer.SharedArrayBuffer 📋Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.SharedArrayBuffer.byteLength 📋Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.SharedArrayBuffer.slice 📋Edge1/15/2020 Firefox7/28/2020195
javascript.builtins.WeakRef 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.WeakRef.WeakRef 📋Edge7/16/2020 Firefox7/28/202012
javascript.builtins.WeakRef.deref 📋Edge7/16/2020 Firefox7/28/202012

2020/6

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Atomics 📋Edge1/15/2020 Firefox6/30/2020167
Safari: Before Safari 16.4, Atomics is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.Safari on iOS: Before Safari on iOS 16.4, Atomics is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.WebView on iOS: Before WebView on iOS 16.4, Atomics is gated behind COOP/COEP. For more detail, read Making your website "cross-origin isolated" using COOP and COEP.
javascript.builtins.Atomics.add 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.and 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.compareExchange 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.exchange 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.isLockFree 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.load 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.notify 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.or 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.store 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.sub 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.wait 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Atomics.xor 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.ListFormat 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the ListFormat() constructor for more details.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.ListFormat.ListFormat 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the ListFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.ListFormat.format 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the ListFormat() constructor for more details.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.ListFormat.formatToParts 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the ListFormat() constructor for more details.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.ListFormat.resolvedOptions 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the ListFormat() constructor for more details.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.ListFormat.supportedLocalesOf 📋Edge1/15/2020 Firefox6/30/2020167
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.Safari: Only available on macOS Big Sur (11) and above.
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_compactDisplay_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_currencySign_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_notation_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_signDisplay_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_unitDisplay_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_unit_parameter Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.RegExp.dotAll 📋Edge1/15/2020 Firefox6/30/2020167
javascript.builtins.Symbol.toStringTag.dom_objects Edge1/15/2020 Firefox6/30/2020167
javascript.regular_expressions.lookbehind_assertion 📋Edge1/15/2020 Firefox6/30/2020167
javascript.regular_expressions.named_backreference 📋Edge1/15/2020 Firefox6/30/2020167
javascript.regular_expressions.named_capturing_group 📋Edge1/15/2020 Firefox6/30/2020167
javascript.regular_expressions.unicode_character_class_escape 📋Edge1/15/2020 Firefox6/30/2020167

2020/5

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_calendar_parameter Edge2/7/2020 Firefox5/5/202088
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_numberingSystem_parameter Edge2/7/2020 Firefox5/5/202088
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_numberingSystem_parameter Edge7/29/2015 Firefox5/5/20201742
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.options_parameter.options_numberingSystem_parameter Edge1/15/2020 Firefox5/5/2020111

2020/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.Locale 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.Locale 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.baseName 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.calendar 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.caseFirst 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.collation 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.hourCycle 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.language 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.maximize 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.minimize 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.numberingSystem 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.numeric 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.region 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.script 📋Edge1/15/2020 Firefox4/7/202083
javascript.builtins.Intl.Locale.toString 📋Edge1/15/2020 Firefox4/7/202083
javascript.classes.static.class_fields 📋Edge1/15/2020 Firefox4/7/202083

2020/3

API First Browser Date Last Browser Date Days Notes
javascript.operators.optional_chaining 📋Edge2/7/2020 Firefox3/10/202032

2020/2

API First Browser Date Last Browser Date Days Notes
javascript.operators.nullish_coalescing 📋Firefox1/7/2020 Edge2/7/202031

2020/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.@@species 📋Firefox8/2/2016 Edge1/15/20201261
javascript.builtins.Array.flat 📋Firefox9/5/2018 Edge1/15/2020497
javascript.builtins.Array.flatMap 📋Firefox9/5/2018 Edge1/15/2020497
javascript.builtins.Array.sort.stable_sorting Firefox6/17/2008 Edge1/15/20204229
javascript.builtins.Array.toLocaleString.locales_parameter Firefox3/7/2017 Edge1/15/20201044
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Array.toLocaleString.options_parameter Firefox3/7/2017 Edge1/15/20201044
javascript.builtins.AsyncGenerator 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncGenerator.next 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncGenerator.return 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncGenerator.throw 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncGeneratorFunction 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncGeneratorFunction.AsyncGeneratorFunction 📋Firefox8/8/2017 Edge1/15/2020890
javascript.builtins.AsyncIterator 📋Firefox11/14/2017 Edge1/15/2020792
javascript.builtins.AsyncIterator.@@asyncIterator 📋Firefox11/14/2017 Edge1/15/2020792
javascript.builtins.BigInt 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.BigInt 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.asIntN 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.asUintN 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.toLocaleString 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.toLocaleString.locales_parameter Firefox10/22/2019 Edge1/15/202085
Deno: Only the locale data for en-US is available.
javascript.builtins.BigInt.toLocaleString.options_parameter Firefox10/22/2019 Edge1/15/202085
javascript.builtins.BigInt.toString 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt.valueOf 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt64Array 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigInt64Array.BigInt64Array 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigUint64Array 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.BigUint64Array.BigUint64Array 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.DataView.getBigInt64 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.DataView.getBigUint64 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.DataView.setBigInt64 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.DataView.setBigUint64 📋Firefox7/9/2019 Edge1/15/2020190
javascript.builtins.Function.name.inferred_names Firefox4/19/2017 Edge1/15/20201001
Edge: Names for functions defined in a dictionary are properly assigned; however, anonymous functions defined on a var/let variable assignment have blank names.
javascript.builtins.Function.toString.toString_revision Firefox6/13/2017 Edge1/15/2020946
javascript.builtins.Intl.Collator.Collator.options_ignorePunctuation_parameter Firefox4/29/2014 Edge1/15/20202087
javascript.builtins.Intl.Collator.Collator.options_localeMatcher_parameter Firefox4/29/2014 Edge1/15/20202087
javascript.builtins.Intl.Collator.Collator.options_numeric_parameter Firefox4/29/2014 Edge1/15/20202087
javascript.builtins.Intl.Collator.Collator.options_sensitivity_parameter Firefox4/29/2014 Edge1/15/20202087
javascript.builtins.Intl.Collator.Collator.options_usage_parameter Firefox4/29/2014 Edge1/15/20202087
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_currencyDisplay_parameter Firefox11/3/2015 Edge1/15/20201534
Safari: Doesn't support currencyDisplay: 'narrowSymbol'.Safari on iOS: Doesn't support currencyDisplay: 'narrowSymbol'.WebView on iOS: Doesn't support currencyDisplay: 'narrowSymbol'.
javascript.builtins.Intl.RelativeTimeFormat 📋Firefox1/29/2019 Edge1/15/2020351
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the RelativeTimeFormat() constructor for more details.
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat 📋Firefox1/29/2019 Edge1/15/2020351
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.locales_parameter Firefox1/29/2019 Edge1/15/2020351
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the RelativeTimeFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.options_parameter.options_localeMatcher_parameter Firefox1/29/2019 Edge1/15/2020351
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.options_parameter.options_numeric_parameter Firefox1/29/2019 Edge1/15/2020351
javascript.builtins.Intl.RelativeTimeFormat.format 📋Firefox1/29/2019 Edge1/15/2020351
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the RelativeTimeFormat() constructor for more details.
javascript.builtins.Intl.RelativeTimeFormat.formatToParts 📋Firefox10/22/2019 Edge1/15/202085
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the RelativeTimeFormat() constructor for more details.
javascript.builtins.Intl.RelativeTimeFormat.resolvedOptions 📋Firefox1/29/2019 Edge1/15/2020351
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the RelativeTimeFormat() constructor for more details.
javascript.builtins.Intl.RelativeTimeFormat.supportedLocalesOf 📋Firefox1/29/2019 Edge1/15/2020351
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.JSON.json_superset Firefox9/5/2018 Edge1/15/2020497
javascript.builtins.JSON.stringify.well_formed_stringify Firefox12/11/2018 Edge1/15/2020400
javascript.builtins.Object.fromEntries 📋Firefox10/23/2018 Edge1/15/2020449
javascript.builtins.Promise.@@species 📋Firefox8/2/2016 Edge1/15/20201261
javascript.builtins.Promise.allSettled 📋Firefox12/10/2019 Edge1/15/202036
javascript.builtins.Proxy.handler.getPrototypeOf 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.RegExp.@@matchAll 📋Firefox5/21/2019 Edge1/15/2020239
javascript.builtins.RegExp.@@replace 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.RegExp.@@split 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.RegExp.flags 📋Firefox3/31/2015 Edge1/15/20201751
javascript.builtins.String.matchAll 📋Firefox5/21/2019 Edge1/15/2020239
javascript.builtins.String.trimEnd 📋Firefox6/26/2018 Edge1/15/2020568
javascript.builtins.String.trimStart 📋Firefox6/26/2018 Edge1/15/2020568
javascript.builtins.Symbol.asyncIterator 📋Firefox11/14/2017 Edge1/15/2020792
javascript.builtins.Symbol.description 📋Firefox10/23/2018 Edge1/15/2020449
Safari: No support for an undefined description.Safari on iOS: No support for an undefined description.WebView on iOS: No support for an undefined description.
javascript.builtins.Symbol.match 📋Firefox8/11/2015 Edge1/15/20201618
javascript.builtins.Symbol.matchAll 📋Firefox5/21/2019 Edge1/15/2020239
javascript.builtins.Symbol.replace 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.Symbol.search 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.Symbol.split 📋Firefox9/20/2016 Edge1/15/20201212
javascript.builtins.globalThis 📋Firefox1/29/2019 Edge1/15/2020351
javascript.classes.public_class_fields 📋Firefox9/3/2019 Edge1/15/2020134
Safari: Parentheses in field initializers can lead to ReferenceErrors. See bug 236843.Safari: Doesn't support public static fields. See bug 194095.Safari on iOS: Parentheses in field initializers can lead to ReferenceErrors. See bug 236843.Safari on iOS: Doesn't support public static fields. See bug 194095.WebView on iOS: Parentheses in field initializers can lead to ReferenceErrors. See bug 236843.WebView on iOS: Doesn't support public static fields. See bug 194095.
javascript.functions.method_definitions.async_generator_methods Firefox11/14/2017 Edge1/15/2020792
javascript.functions.rest_parameters.destructuring Firefox3/7/2017 Edge1/15/20201044
javascript.grammar.hashbang_comments 📋Firefox5/21/2019 Edge1/15/2020239
javascript.grammar.numeric_separators 📋Firefox10/22/2019 Edge1/15/202085
javascript.grammar.template_literals.template_literal_revision Firefox4/19/2017 Edge1/15/20201001
javascript.operators.async_generator_function 📋Firefox11/14/2017 Edge1/15/2020792
javascript.operators.destructuring.rest_in_objects Firefox8/8/2017 Edge1/15/2020890
javascript.operators.generator_function.trailing_comma Firefox3/7/2017 Edge1/15/20201044
javascript.operators.import 📋Firefox5/21/2019 Edge1/15/2020239
Deno: Bundled Deno applications (using deno compile) do not support dynamic importsNode.js: Dynamic import can be used in either CommonJS or ES module files, to import either CommonJS or ES module files. See Node's ECMAScript Modules documentation for more details.Node.js: Dynamic import can be used in either CommonJS or ES module files, to import either CommonJS or ES module files. See Node's ECMAScript Modules documentation for more details.
javascript.operators.import_meta 📋Firefox9/5/2018 Edge1/15/2020497
javascript.operators.object_initializer.spread_properties Firefox8/8/2017 Edge1/15/2020890
javascript.operators.spread.spread_in_object_literals 📋Firefox8/8/2017 Edge1/15/2020890
javascript.statements.async_generator_function 📋Firefox11/14/2017 Edge1/15/2020792
javascript.statements.for_await_of 📋Firefox11/14/2017 Edge1/15/2020792
javascript.statements.try_catch.optional_catch_binding Firefox1/23/2018 Edge1/15/2020722

2018/10

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.Collator.Collator.options_caseFirst_parameter Firefox8/8/2017 Edge10/2/2018420
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_hourCycle_parameter Firefox1/23/2018 Edge10/2/2018252
javascript.builtins.Intl.DateTimeFormat.formatToParts 📋Firefox1/24/2017 Edge10/2/2018616
Chrome: Before version 71, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 71 and later use the specification defined dayPeriod. See bug 41402623.Chrome Android: Before version 71, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 71 and later use the specification defined dayPeriod. See bug 41402623.Node.js: Before version 12.0.0, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 12.0.0 and later use the specification defined dayPeriod. See bug 41402623.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.Quest Browser: Before version 6.0, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 71 and later use the specification defined dayPeriod. See bug 41402623.Opera: Before version 58, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 58 and later use the specification defined dayPeriod. See bug 41402623.Opera Android: Before version 50, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 50 and later use the specification defined dayPeriod. See bug 41402623.Samsung Internet: Before version 71, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 71 and later use the specification defined dayPeriod. See bug 41402623.WebView Android: Before version 71, formatToParts() returned an object with an incorrectly cased type key of dayperiod. Version 71 and later use the specification defined dayPeriod. See bug 41402623.
javascript.builtins.Intl.PluralRules 📋Firefox1/23/2018 Edge10/2/2018252
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the PluralRules() constructor for more details.
javascript.builtins.Intl.PluralRules.PluralRules 📋Firefox1/23/2018 Edge10/2/2018252
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the PluralRules instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.PluralRules.resolvedOptions 📋Firefox1/23/2018 Edge10/2/2018252
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the PluralRules() constructor for more details.
javascript.builtins.Intl.PluralRules.select 📋Firefox1/23/2018 Edge10/2/2018252
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the PluralRules() constructor for more details.
javascript.builtins.Intl.PluralRules.supportedLocalesOf 📋Firefox1/23/2018 Edge10/2/2018252
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the PluralRules() constructor for more details.
javascript.builtins.Promise.finally 📋Firefox1/23/2018 Edge10/2/2018252

2018/5

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.values 📋Edge8/2/2016 Firefox5/9/2018645
javascript.statements.export 📋Edge10/17/2017 Firefox5/9/2018204
Node.js: Modules must either have a filename ending in .mjs, or the nearest parent package.json file must contain "type": "module". See Node's ECMAScript Modules documentation for more details.
javascript.statements.export.default 📋Edge10/17/2017 Firefox5/9/2018204
Node.js: Modules must either have a filename ending in .mjs, or the nearest parent package.json file must contain "type": "module". See Node's ECMAScript Modules documentation for more details.
javascript.statements.import 📋Edge10/17/2017 Firefox5/9/2018204
Node.js: Modules must either have a filename ending in .mjs, or the nearest parent package.json file must contain "type": "module". See Node's ECMAScript Modules documentation for more details.Node.js: Modules must either have a filename ending in .mjs, or the nearest parent package.json file must contain "type": "module". See Node's ECMAScript Modules documentation for more details.

2018/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.NumberFormat.formatToParts 📋Edge7/29/2015 Firefox1/23/2018909
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the NumberFormat() constructor for more details.

2017/11

API First Browser Date Last Browser Date Days Notes
javascript.statements.for_of.async_iterators Edge7/29/2015 Firefox11/14/2017839

2017/10

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.getCanonicalLocales 📋Firefox8/2/2016 Edge10/17/2017441
javascript.operators.destructuring.rest_in_arrays Firefox9/22/2015 Edge10/17/2017756

2017/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Float32Array.Float32Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Float64Array.Float64Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Int16Array.Int16Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Int32Array.Int32Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Int8Array.Int8Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.String.toLocaleLowerCase.locales_parameter Edge7/29/2015 Firefox8/8/2017741
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.String.toLocaleUpperCase.locales_parameter Edge7/29/2015 Firefox8/8/2017741
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.TypedArray.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Uint16Array.Uint16Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Uint32Array.Uint32Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Uint8Array.Uint8Array.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray.constructor_without_parameters Edge7/29/2015 Firefox8/8/2017741

2017/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Intl.DateTimeFormat.resolvedOptions.computed_timezone Edge8/2/2016 Firefox4/19/2017260
javascript.statements.for_of.closing_iterators Edge8/2/2016 Firefox4/19/2017260
javascript.builtins.AsyncFunction 📋Firefox3/7/2017 Edge4/5/201729
javascript.builtins.AsyncFunction.AsyncFunction 📋Firefox3/7/2017 Edge4/5/201729
javascript.builtins.Date.@@toPrimitive 📋Firefox1/26/2016 Edge4/5/2017435
javascript.builtins.Date.UTC.optional_monthIndex Firefox3/22/2011 Edge4/5/20172206
javascript.builtins.Function.@@hasInstance 📋Firefox11/15/2016 Edge4/5/2017141
javascript.builtins.Object.getOwnPropertyDescriptors 📋Firefox11/15/2016 Edge4/5/2017141
javascript.builtins.String.padEnd 📋Firefox8/2/2016 Edge4/5/2017246
javascript.builtins.String.padStart 📋Firefox8/2/2016 Edge4/5/2017246
javascript.builtins.Symbol.@@toPrimitive 📋Firefox1/26/2016 Edge4/5/2017435
javascript.builtins.Symbol.hasInstance 📋Firefox11/15/2016 Edge4/5/2017141
javascript.builtins.Symbol.isConcatSpreadable 📋Firefox8/2/2016 Edge4/5/2017246
javascript.builtins.Symbol.toPrimitive 📋Firefox1/26/2016 Edge4/5/2017435
javascript.builtins.Symbol.toStringTag 📋Firefox1/24/2017 Edge4/5/201771
javascript.functions.method_definitions.async_methods Firefox3/7/2017 Edge4/5/201729
javascript.operators.async_function 📋Firefox3/7/2017 Edge4/5/201729
javascript.statements.async_function 📋Firefox3/7/2017 Edge4/5/201729

2017/3

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Date.toLocaleDateString.iana_time_zone_names Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Date.toLocaleString.iana_time_zone_names Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Date.toLocaleTimeString.iana_time_zone_names Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Float32Array.Float32Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Float64Array.Float64Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Int16Array.Int16Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Int32Array.Int32Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Int8Array.Int8Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZone_parameter.iana_time_zones Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.TypedArray.iterable_in_constructor Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Uint16Array.Uint16Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Uint32Array.Uint32Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Uint8Array.Uint8Array.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray.iterable_allowed Edge8/2/2016 Firefox3/7/2017217
javascript.functions.arrow_functions.trailing_comma Edge7/29/2015 Firefox3/7/2017587
javascript.grammar.trailing_commas.trailing_commas_in_functions Edge8/2/2016 Firefox3/7/2017217
javascript.operators.await 📋Edge8/2/2016 Firefox3/7/2017217
javascript.operators.exponentiation 📋Edge8/2/2016 Firefox3/7/2017217
javascript.operators.exponentiation_assignment 📋Edge8/2/2016 Firefox3/7/2017217
javascript.operators.function.trailing_comma Edge8/2/2016 Firefox3/7/2017217
javascript.statements.function.trailing_comma_in_parameters Edge8/2/2016 Firefox3/7/2017217
javascript.statements.generator_function.trailing_comma_in_parameters Edge8/2/2016 Firefox3/7/2017217

2017/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.TypedArray.toLocaleString 📋Edge7/29/2015 Firefox1/24/2017545
javascript.builtins.TypedArray.toString 📋Edge7/29/2015 Firefox1/24/2017545

2016/9

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Proxy.handler.setPrototypeOf 📋Edge7/29/2015 Firefox9/20/2016419
javascript.builtins.RegExp.@@match 📋Edge11/12/2015 Firefox9/20/2016313
javascript.builtins.RegExp.@@search 📋Edge11/12/2015 Firefox9/20/2016313
javascript.builtins.RegExp.@@species 📋Edge11/12/2015 Firefox9/20/2016313

2016/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array.@@unscopables 📋Edge7/29/2015 Firefox8/2/2016370
javascript.builtins.Array.includes 📋Firefox12/15/2015 Edge8/2/2016231
javascript.builtins.ArrayBuffer.@@species 📋Edge11/12/2015 Firefox8/2/2016264
javascript.builtins.Function.name 📋Firefox11/9/2004 Edge8/2/20164284
javascript.builtins.Function.name.configurable_true Firefox5/12/2015 Edge8/2/2016448
javascript.builtins.Object.entries 📋Firefox6/7/2016 Edge8/2/201656
javascript.builtins.Object.values 📋Firefox6/7/2016 Edge8/2/201656
javascript.builtins.Symbol.unscopables 📋Edge7/29/2015 Firefox8/2/2016370
javascript.builtins.TypedArray.@@species 📋Edge11/12/2015 Firefox8/2/2016264
javascript.builtins.TypedArray.includes 📋Firefox12/15/2015 Edge8/2/2016231
javascript.functions.default_parameters 📋Firefox8/28/2012 Edge8/2/20161435
javascript.functions.default_parameters.destructured_parameter_with_default_value_assignment Firefox9/22/2015 Edge8/2/2016315
javascript.functions.default_parameters.parameters_without_defaults_after_default_parameters Firefox12/10/2013 Edge8/2/2016966
javascript.operators.destructuring 📋Firefox9/22/2015 Edge8/2/2016315
Firefox: Firefox provided a non-standard destructuring implementation from Firefox 2 to 40.Firefox for Android: Firefox for Android provided a non-standard destructuring implementation from Firefox for Android 4 to 40.
javascript.operators.destructuring.computed_property_names Firefox9/22/2015 Edge8/2/2016315
javascript.statements.let 📋Firefox1/26/2016 Edge8/2/2016189
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Edge: In Edge 12 and 13, let within a for loop initializer does not create a separate variable for each loop iteration as defined by ES2015. Instead, it behaves as though the loop were wrapped in a scoping block with the let immediately before the loop.Firefox: Before Firefox 44, let is only available to code blocks in HTML wrapped in a <script type="application/javascript;version=1.7"> block (or higher version) and has different semantics (e.g. no temporal dead zone).Firefox: Before Firefox 46, a TypeError is thrown on redeclaration instead of a SyntaxError.Firefox: Firefox 54 adds support of let in workers.Firefox for Android: Before Firefox for Android 44, let is only available to code blocks in HTML wrapped in a <script type="application/javascript;version=1.7"> block (or higher version) and has different semantics (e.g. no temporal dead zone).Firefox for Android: Before Firefox for Android 46, a TypeError is thrown on redeclaration instead of a SyntaxError.Firefox for Android: Firefox for Android 54 adds support of let in workers.Internet Explorer: In Internet Explorer, let within a for loop initializer does not create a separate variable for each loop iteration as defined by ES2015. Instead, it behaves as though the loop were wrapped in a scoping block with the let immediately before the loop.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.

2016/4

API First Browser Date Last Browser Date Days Notes
javascript.builtins.RegExp.unicode 📋Edge7/29/2015 Firefox4/26/2016272
Edge: Case folding is implemented in version 13Node.js: Case folding is implemented in version 8.6.0
javascript.builtins.TypedArray.sort 📋Edge7/29/2015 Firefox4/26/2016272
javascript.functions.arguments.@@iterator 📋Edge7/29/2015 Firefox4/26/2016272
javascript.functions.block_level_functions Edge7/29/2015 Firefox4/26/2016272
javascript.regular_expressions.character_escape.unicode Edge7/29/2015 Firefox4/26/2016272

2016/3

API First Browser Date Last Browser Date Days Notes
javascript.classes 📋Edge11/12/2015 Firefox3/8/2016117
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Opera: Strict mode is required.Opera Android: Strict mode is required.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.
javascript.classes.constructor 📋Edge11/12/2015 Firefox3/8/2016117
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Opera: Strict mode is required.Opera Android: Strict mode is required.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.
javascript.classes.extends 📋Edge11/12/2015 Firefox3/8/2016117
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Opera: Strict mode is required.Opera Android: Strict mode is required.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.
javascript.classes.static 📋Edge11/12/2015 Firefox3/8/2016117
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Opera: Strict mode is required.Opera Android: Strict mode is required.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.
javascript.operators.class 📋Edge11/12/2015 Firefox3/8/2016117
javascript.operators.super 📋Edge11/12/2015 Firefox3/8/2016117
javascript.statements.class 📋Edge11/12/2015 Firefox3/8/2016117
Chrome: Strict mode is required.Chrome Android: Strict mode is required.Opera: Strict mode is required.Opera Android: Strict mode is required.Samsung Internet: Strict mode is required.WebView Android: Strict mode is required.

2016/1

API First Browser Date Last Browser Date Days Notes
javascript.builtins.RegExp.sticky.anchored_sticky_flag Edge11/12/2015 Firefox1/26/201675

2015/12

API First Browser Date Last Browser Date Days Notes
javascript.functions.method_definitions.generator_methods_not_constructable Edge11/12/2015 Firefox12/15/201533
javascript.statements.generator_function.not_constructable_with_new Edge11/12/2015 Firefox12/15/201533

2015/11

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Generator 📋Firefox12/10/2013 Edge11/12/2015702
javascript.builtins.Generator.next 📋Firefox12/10/2013 Edge11/12/2015702
javascript.builtins.Generator.return 📋Firefox5/12/2015 Edge11/12/2015184
javascript.builtins.Generator.throw 📋Firefox12/10/2013 Edge11/12/2015702
javascript.builtins.GeneratorFunction 📋Firefox12/10/2013 Edge11/12/2015702
javascript.builtins.GeneratorFunction.GeneratorFunction 📋Firefox12/10/2013 Edge11/12/2015702
javascript.builtins.Map.@@species 📋Firefox9/22/2015 Edge11/12/201551
javascript.builtins.RegExp.sticky 📋Firefox6/17/2008 Edge11/12/20152704
javascript.builtins.RegExp.sticky.prototype_accessor Firefox5/12/2015 Edge11/12/2015184
javascript.builtins.Set.@@species 📋Firefox9/22/2015 Edge11/12/201551
javascript.builtins.Symbol.species 📋Firefox9/22/2015 Edge11/12/201551
javascript.operators.new_target 📋Firefox9/22/2015 Edge11/12/201551
javascript.statements.generator_function 📋Firefox12/10/2013 Edge11/12/2015702
javascript.statements.generator_function.IteratorResult_object Firefox4/29/2014 Edge11/12/2015562
javascript.builtins.Reflect 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.apply 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.construct 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.defineProperty 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.deleteProperty 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.get 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.getOwnPropertyDescriptor 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.getPrototypeOf 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.has 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.isExtensible 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.ownKeys 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.preventExtensions 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.set 📋Edge7/29/2015 Firefox11/3/201597
javascript.builtins.Reflect.setPrototypeOf 📋Edge7/29/2015 Firefox11/3/201597

2015/9

API First Browser Date Last Browser Date Days Notes
javascript.builtins.RegExp.source.prototype_accessor Edge7/29/2015 Firefox9/22/201555

2015/8

API First Browser Date Last Browser Date Days Notes
javascript.builtins.String.includes 📋Edge7/29/2015 Firefox8/11/201513
javascript.builtins.String.unicode_code_point_escapes Edge7/29/2015 Firefox8/11/201513
javascript.grammar.unicode_point_escapes 📋Edge7/29/2015 Firefox8/11/201513

2015/7

API First Browser Date Last Browser Date Days Notes
javascript.builtins.Array 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.Array.Array 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.concat 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.copyWithin 📋Firefox9/2/2014 Edge7/29/2015330
javascript.builtins.Array.entries 📋Firefox3/18/2014 Edge7/29/2015498
javascript.builtins.Array.every 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.fill 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Array.filter 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.find 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Array.findIndex 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Array.forEach 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.from 📋Firefox9/2/2014 Edge7/29/2015330
javascript.builtins.Array.indexOf 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.isArray 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Array.join 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.keys 📋Firefox3/18/2014 Edge7/29/2015498
javascript.builtins.Array.lastIndexOf 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.length 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.map 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.of 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Array.pop 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.push 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.reduce 📋Firefox6/17/2008 Edge7/29/20152598
javascript.builtins.Array.reduceRight 📋Firefox6/17/2008 Edge7/29/20152598
javascript.builtins.Array.reverse 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.shift 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.slice 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.some 📋Firefox11/29/2005 Edge7/29/20153529
javascript.builtins.Array.sort 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.splice 📋Firefox11/9/2004 Edge7/29/20153914
Internet Explorer: From Internet Explorer 5.5 through 8, all elements of the array will not be deleted if deleteCount is omitted. This behavior was fixed in Internet Explorer 9.
javascript.builtins.Array.toLocaleString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Array.unshift 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.ArrayBuffer 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.ArrayBuffer.ArrayBuffer 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.ArrayBuffer.byteLength 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.ArrayBuffer.isView 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.ArrayBuffer.slice 📋Firefox4/24/2012 Edge7/29/20151191
Firefox: The non-standard ArrayBuffer.slice() method has been removed in Firefox 53 (but the standardized version ArrayBuffer.prototype.slice() is kept.Firefox for Android: The non-standard ArrayBuffer.slice() method has been removed in Firefox for Android 53 (but the standardized version ArrayBuffer.prototype.slice() is kept.
javascript.builtins.Boolean 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Boolean.Boolean 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Boolean.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Boolean.valueOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.DataView 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.DataView 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.buffer 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.byteLength 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.byteOffset 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getFloat32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getFloat64 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getInt16 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getInt32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getInt8 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getUint16 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getUint32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.getUint8 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setFloat32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setFloat64 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setInt16 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setInt32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setInt8 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setUint16 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setUint32 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.DataView.setUint8 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.Date 📋Firefox11/9/2004 Edge7/29/20153914
Internet Explorer: The ISO8601 Date Format is not supported in Internet Explorer 8 or earlier.
javascript.builtins.Date.Date 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.UTC 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getDate 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getDay 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getFullYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getHours 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getMilliseconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getMinutes 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getMonth 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getSeconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getTime 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getTimezoneOffset 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCDate 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCDay 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCFullYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCHours 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCMilliseconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCMinutes 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCMonth 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getUTCSeconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.getYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.now 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.parse 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.parse.iso_8601 Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Date.setDate 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setFullYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setHours 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setMilliseconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setMinutes 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setMonth 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setSeconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setTime 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCDate 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCFullYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCHours 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCMilliseconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCMinutes 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCMonth 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setUTCSeconds 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.setYear 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toDateString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toGMTString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toISOString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toJSON 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toLocaleDateString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toLocaleDateString.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Date.toLocaleDateString.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Date.toLocaleString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toLocaleString.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Date.toLocaleString.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Date.toLocaleTimeString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toLocaleTimeString.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Date.toLocaleTimeString.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Date.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toTimeString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.toUTCString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Date.valueOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error.Error 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error.message 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error.name 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error.stack Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Error.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.EvalError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.EvalError.EvalError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Float32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Float32Array.Float32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Float64Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Float64Array.Float64Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Function 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.Function 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.apply 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.apply.generic_arrays_as_arguments Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Function.arguments Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.bind 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Function.call 📋Firefox11/9/2004 Edge7/29/20153914
Node.js: When calling this method, thisArg does not default to the global object.
javascript.builtins.Function.caller Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.length 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Function.length.configurable_true Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.Function.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Infinity 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Int16Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Int16Array.Int16Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Int32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Int32Array.Int32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Int8Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Int8Array.Int8Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Intl 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.Collator 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the Collator() constructor for more details.
javascript.builtins.Intl.Collator.Collator 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the Collator instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.Collator.compare 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the Collator() constructor for more details.
javascript.builtins.Intl.Collator.resolvedOptions 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the Collator() constructor for more details.
javascript.builtins.Intl.Collator.supportedLocalesOf 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.DateTimeFormat 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the DateTimeFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the DateTimeFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZoneName_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZone_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.DateTimeFormat.format 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.
javascript.builtins.Intl.DateTimeFormat.resolvedOptions 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the DateTimeFormat() constructor for more details.
javascript.builtins.Intl.DateTimeFormat.supportedLocalesOf 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.NumberFormat 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the NumberFormat() constructor for more details.
javascript.builtins.Intl.NumberFormat.NumberFormat 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the NumberFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_currency_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_localeMatcher_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_maximumFractionDigits_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_maximumSignificantDigits_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumFractionDigits_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumIntegerDigits_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumSignificantDigits_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_style_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_useGrouping_parameter Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the NumberFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Intl.NumberFormat.format 📋Firefox4/29/2014 Edge7/29/2015456
Edge: Before Edge 18, numbers are rounded to 15 decimal digits. For example, new Intl.NumberFormat('en-US').format(1000000000000005) returns "1,000,000,000,000,010".Internet Explorer: In Internet Explorer 11, numbers are rounded to 15 decimal digits. For example, new Intl.NumberFormat('en-US').format(1000000000000005) returns "1,000,000,000,000,010".Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the NumberFormat() constructor for more details.
javascript.builtins.Intl.NumberFormat.resolvedOptions 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. See the NumberFormat() constructor for more details.
javascript.builtins.Intl.NumberFormat.supportedLocalesOf 📋Firefox4/29/2014 Edge7/29/2015456
Node.js: Before version 13.0.0, only the locale data for en-US is available by default. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Iterator 📋Firefox11/20/2012 Edge7/29/2015981
javascript.builtins.Iterator.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.JSON 📋Firefox6/30/2009 Edge7/29/20152220
javascript.builtins.JSON.parse 📋Firefox6/30/2009 Edge7/29/20152220
javascript.builtins.JSON.stringify 📋Firefox6/30/2009 Edge7/29/20152220
javascript.builtins.Map 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.Map.Map 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.Map.iterable_allowed Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.Map.null_allowed Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.Map.clear 📋Firefox2/19/2013 Edge7/29/2015890
javascript.builtins.Map.delete 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.entries 📋Firefox4/2/2013 Edge7/29/2015848
javascript.builtins.Map.forEach 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Map.get 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.has 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Map.key_equality_for_zeros Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Map.keys 📋Firefox4/2/2013 Edge7/29/2015848
javascript.builtins.Map.set 📋Firefox6/5/2012 Edge7/29/20151149
Internet Explorer: Returns 'undefined' instead of the 'Map' object.
javascript.builtins.Map.size 📋Firefox2/19/2013 Edge7/29/2015890
Firefox: From Firefox 13 to Firefox 18, the size property was implemented as a Map.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.Firefox for Android: From Firefox for Android 14 to Firefox for Android 18, the size property was implemented as a Map.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.
javascript.builtins.Map.values 📋Firefox4/2/2013 Edge7/29/2015848
javascript.builtins.Math 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.E 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.LN10 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.LN2 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.LOG10E 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.LOG2E 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.PI 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.SQRT1_2 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.SQRT2 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.abs 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.acos 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.acosh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.asin 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.asinh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.atan 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.atan2 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.atanh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.cbrt 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.ceil 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.clz32 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Math.cos 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.cosh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.exp 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.expm1 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.floor 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.fround 📋Firefox12/10/2013 Edge7/29/2015596
javascript.builtins.Math.hypot 📋Firefox2/4/2014 Edge7/29/2015540
javascript.builtins.Math.imul 📋Firefox4/2/2013 Edge7/29/2015848
javascript.builtins.Math.log 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.log10 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.log1p 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.log2 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.max 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.min 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.pow 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.random 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.round 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.sign 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.sin 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.sinh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.sqrt 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.tan 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Math.tanh 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Math.trunc 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.NaN 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.EPSILON 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Number.MAX_SAFE_INTEGER 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Number.MAX_VALUE 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.MIN_SAFE_INTEGER 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Number.MIN_VALUE 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.NEGATIVE_INFINITY 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.NaN 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.Number 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.POSITIVE_INFINITY 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.isFinite 📋Firefox10/9/2012 Edge7/29/20151023
javascript.builtins.Number.isInteger 📋Firefox10/9/2012 Edge7/29/20151023
javascript.builtins.Number.isNaN 📋Firefox8/28/2012 Edge7/29/20151065
javascript.builtins.Number.isSafeInteger 📋Firefox9/2/2014 Edge7/29/2015330
javascript.builtins.Number.parseFloat 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Number.parseInt 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Number.toExponential 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.toFixed 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.toLocaleString 📋Firefox11/9/2004 Edge7/29/20153914
Edge: Before Edge 18, numbers are rounded to 15 decimal digits. For example, (1000000000000005).toLocaleString('en-US') returns "1,000,000,000,000,010".Internet Explorer: In Internet Explorer 11, numbers are rounded to 15 decimal digits. For example, (1000000000000005).toLocaleString('en-US') returns "1,000,000,000,000,010".
javascript.builtins.Number.toLocaleString.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.Number.toLocaleString.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Number.toPrecision 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Number.valueOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.Object 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.assign 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.Object.constructor 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.create 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.defineGetter 📋Firefox11/9/2004 Edge7/29/20153914
Firefox: Starting with Firefox 48, this method can no longer be called at the global scope without any object. A TypeError will be thrown otherwise. Previously, the global object was used in these cases automatically, but this is no longer the case.
javascript.builtins.Object.defineProperties 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.defineProperty 📋Firefox3/22/2011 Edge7/29/20151590
Internet Explorer: In Internet Explorer 8, this was only supported on DOM objects and with some non-standard behaviors. This was later fixed in Internet Explorer 9.Safari: Also supported in Safari 5, but not on DOM objects.Safari on iOS: Also supported in Safari for iOS 4.2, but not on DOM objects.WebView on iOS: Also supported in Safari for iOS 4.2, but not on DOM objects.
javascript.builtins.Object.defineSetter 📋Firefox11/9/2004 Edge7/29/20153914
Firefox: Starting with Firefox 48, this method can no longer be called at the global scope without any object. A TypeError will be thrown otherwise. Previously, the global object was used in these cases automatically, but this is no longer the case.
javascript.builtins.Object.freeze 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.getOwnPropertyDescriptor 📋Firefox3/22/2011 Edge7/29/20151590
Internet Explorer: In Internet Explorer 8, this was only supported on DOM objects and with some non-standard behaviors. This was later fixed in Internet Explorer 9.
javascript.builtins.Object.getOwnPropertyNames 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.getOwnPropertySymbols 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Object.getPrototypeOf 📋Firefox6/30/2009 Edge7/29/20152220
javascript.builtins.Object.hasOwnProperty 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.is 📋Firefox6/25/2013 Edge7/29/2015764
javascript.builtins.Object.isExtensible 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.isFrozen 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.isPrototypeOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.isSealed 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.keys 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.lookupGetter 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.lookupSetter 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.preventExtensions 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.preventExtensions.ES2015_behavior Firefox1/13/2015 Edge7/29/2015197
javascript.builtins.Object.propertyIsEnumerable 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.proto 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.seal 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Object.setPrototypeOf 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Object.toLocaleString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Object.valueOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Promise 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.Promise 📋Firefox4/29/2014 Edge7/29/2015456
Firefox: Constructor requires a new operator since version 37.Firefox for Android: Constructor requires a new operator since version 37.Node.js: Constructor requires a new operator since version 4.Safari: Constructor requires a new operator since version 10.Safari on iOS: Constructor requires a new operator since version 10.WebView on iOS: Constructor requires a new operator since version 10.
javascript.builtins.Promise.all 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.catch 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.race 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.reject 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.resolve 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Promise.then 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Proxy 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.Proxy 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.apply 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.construct 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.defineProperty 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.deleteProperty 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.get 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.getOwnPropertyDescriptor 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.has 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.handler.isExtensible 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.Proxy.handler.ownKeys 📋Firefox1/8/2013 Edge7/29/2015932
Firefox: In Firefox 42, the implementation got updated to reflect the final ES2015 specification: The result is now checked if it is an array and if the array elements are either of type string or of type symbol. Enumerating duplicate own property names is not a failure anymore.Firefox for Android: In Firefox for Android 42, the implementation got updated to reflect the final ES2015 specification: The result is now checked if it is an array and if the array elements are either of type string or of type symbol. Enumerating duplicate own property names is not a failure anymore.
javascript.builtins.Proxy.handler.preventExtensions 📋Firefox6/25/2013 Edge7/29/2015764
javascript.builtins.Proxy.handler.set 📋Firefox1/8/2013 Edge7/29/2015932
javascript.builtins.Proxy.revocable 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.RangeError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RangeError.RangeError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.ReferenceError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.ReferenceError.ReferenceError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.RegExp 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.compile 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.exec 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.global 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.global.prototype_accessor Firefox5/12/2015 Edge7/29/201578
javascript.builtins.RegExp.ignoreCase 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.ignoreCase.prototype_accessor Firefox5/12/2015 Edge7/29/201578
javascript.builtins.RegExp.input 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.lastIndex 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.lastMatch 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.lastParen 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.leftContext 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.multiline 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.multiline.prototype_accessor Firefox5/12/2015 Edge7/29/201578
javascript.builtins.RegExp.n 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.rightContext 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.source 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.source.empty_regex_string Firefox5/12/2015 Edge7/29/201578
javascript.builtins.RegExp.source.escaping Firefox5/12/2015 Edge7/29/201578
javascript.builtins.RegExp.test 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.RegExp.toString.escaping Firefox5/12/2015 Edge7/29/201578
javascript.builtins.Set 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Set.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.Set.Set 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Set.Set.iterable_allowed Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Set.Set.null_allowed Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.Set.add 📋Firefox6/5/2012 Edge7/29/20151149
Internet Explorer: Returns 'undefined' instead of the 'Set' object.
javascript.builtins.Set.clear 📋Firefox2/19/2013 Edge7/29/2015890
javascript.builtins.Set.delete 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Set.entries 📋Firefox9/17/2013 Edge7/29/2015680
javascript.builtins.Set.forEach 📋Firefox10/29/2013 Edge7/29/2015638
javascript.builtins.Set.has 📋Firefox6/5/2012 Edge7/29/20151149
javascript.builtins.Set.key_equality_for_zeros Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.Set.keys 📋Firefox9/17/2013 Edge7/29/2015680
javascript.builtins.Set.size 📋Firefox2/19/2013 Edge7/29/2015890
Firefox: From Firefox 13 to Firefox 18, the size property was implemented as a Set.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.Firefox for Android: From Firefox for Android 14 to Firefox for Android 18, the size property was implemented as a Set.prototype.size() method, this has been changed to a property in later versions conform to the ECMAScript 2015 specification.
javascript.builtins.Set.values 📋Firefox9/17/2013 Edge7/29/2015680
javascript.builtins.String 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.String.String 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.anchor 📋Firefox11/9/2004 Edge7/29/20153914
Firefox: Starting with version 17, the quotation mark (") is replaced by its HTML reference character (") in strings supplied for the name parameter.
javascript.builtins.String.big 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.blink 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.bold 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.charAt 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.charCodeAt 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.codePointAt 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.String.concat 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.endsWith 📋Firefox11/20/2012 Edge7/29/2015981
javascript.builtins.String.fixed 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.fontcolor 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.fontsize 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.fromCharCode 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.fromCodePoint 📋Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.String.indexOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.italics 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.lastIndexOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.length 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.link 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.localeCompare 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.localeCompare.locales_parameter Firefox4/29/2014 Edge7/29/2015456
Deno: Only the locale data for en-US is available.Node.js: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the function silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
javascript.builtins.String.localeCompare.options_parameter Firefox4/29/2014 Edge7/29/2015456
javascript.builtins.String.match 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.normalize 📋Firefox7/22/2014 Edge7/29/2015372
javascript.builtins.String.raw 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.String.repeat 📋Firefox9/17/2013 Edge7/29/2015680
javascript.builtins.String.replace 📋Firefox11/9/2004 Edge7/29/20153914
Internet Explorer: A replacement function as second argument is not supported.
javascript.builtins.String.search 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.slice 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.small 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.split 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.startsWith 📋Firefox11/20/2012 Edge7/29/2015981
javascript.builtins.String.strike 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.sub 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.substr 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.substring 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.sup 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.toLocaleLowerCase 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.toLocaleUpperCase 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.toLowerCase 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.toString 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.toUpperCase 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.String.trim 📋Firefox6/30/2009 Edge7/29/20152220
javascript.builtins.String.valueOf 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Symbol 📋Firefox2/24/2015 Edge7/29/2015155
Edge: Edge 12 included Symbol properties in JSON.stringify() output.
javascript.builtins.Symbol.Symbol 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Symbol.for 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Symbol.iterator 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Symbol.keyFor 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Symbol.toString 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.Symbol.valueOf 📋Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.SyntaxError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.SyntaxError.SyntaxError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.TypeError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.TypeError.TypeError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.TypedArray 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.@@iterator 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: A placeholder property named @@iterator is used.Firefox: A placeholder property named iterator is used.Firefox for Android: A placeholder property named @@iterator is used.Firefox for Android: A placeholder property named iterator is used.
javascript.builtins.TypedArray.BYTES_PER_ELEMENT 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.buffer 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.byteLength 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.byteOffset 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.copyWithin 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.TypedArray.entries 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.every 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.fill 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.filter 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.find 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.findIndex 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.forEach 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.from 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.indexOf 📋Firefox3/31/2015 Edge7/29/2015120
Firefox: Starting with Firefox 47, this method will no longer return -0. For example, new Uint8Array([0]).indexOf(0, -0) will now always return +0.Firefox for Android: Starting with Firefox for Android 47, this method will no longer return -0. For example, new Uint8Array([0]).indexOf(0, -0) will now always return +0.
javascript.builtins.TypedArray.index_properties_not_consulting_prototype Firefox10/29/2013 Edge7/29/2015638
Bun: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Chrome: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Chrome Android: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Deno: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Edge: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Internet Explorer: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Node.js: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Quest Browser: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Opera: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Opera Android: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Safari: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Safari on iOS: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.Samsung Internet: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.WebView Android: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.WebView on iOS: Negative integers are not considered as indexed properties and therefore return the value of the prototype property.
javascript.builtins.TypedArray.join 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.keys 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.lastIndexOf 📋Firefox3/31/2015 Edge7/29/2015120
Firefox: Starting with Firefox 47, this method will no longer return -0. For example, new Uint8Array([0]).lastIndexOf(0, -0) will now always return +0.Firefox for Android: Starting with Firefox for Android 47, this method will no longer return -0. For example, new Uint8Array([0]).lastIndexOf(0, -0) will now always return +0.
javascript.builtins.TypedArray.length 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.map 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.name 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.named_properties Firefox6/10/2014 Edge7/29/2015414
javascript.builtins.TypedArray.of 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.reduce 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.reduceRight 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.reverse 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.set 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.slice 📋Firefox5/12/2015 Edge7/29/201578
javascript.builtins.TypedArray.some 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.TypedArray.subarray 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.TypedArray.values 📋Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.URIError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.URIError.URIError 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.Uint16Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint16Array.Uint16Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint32Array.Uint32Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint8Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint8Array.Uint8Array 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint8ClampedArray 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray 📋Firefox3/22/2011 Edge7/29/20151590
javascript.builtins.WeakMap 📋Firefox8/16/2011 Edge7/29/20151443
javascript.builtins.WeakMap.WeakMap 📋Firefox8/16/2011 Edge7/29/20151443
javascript.builtins.WeakMap.WeakMap.iterable_allowed Firefox2/24/2015 Edge7/29/2015155
javascript.builtins.WeakMap.WeakMap.null_allowed Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.WeakMap.delete 📋Firefox8/16/2011 Edge7/29/20151443
Firefox: Before Firefox 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.Firefox for Android: Before Firefox for Android 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.
javascript.builtins.WeakMap.get 📋Firefox8/16/2011 Edge7/29/20151443
Firefox: Before Firefox 38, this method threw a TypeError when the key parameter was not an object. However, the ES2015 specification specifies to return undefined instead. Furthermore, WeakMap.prototype.get accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.Firefox for Android: Before Firefox for Android 38, this method threw a TypeError when the key parameter was not an object. However, the ES2015 specification specifies to return undefined instead. Furthermore, WeakMap.prototype.get accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher.
javascript.builtins.WeakMap.has 📋Firefox8/16/2011 Edge7/29/20151443
Firefox: Before Firefox 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.Firefox for Android: Before Firefox for Android 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.
javascript.builtins.WeakMap.set 📋Firefox8/16/2011 Edge7/29/20151443
Firefox: Before Firefox 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.Firefox for Android: Before Firefox for Android 38, this method threw a TypeError when the key parameter was not an object. This has been fixed in version 38 and later to return false as per the ES2015 standard.Internet Explorer: Returns 'undefined' instead of the 'Map' object.
javascript.builtins.WeakSet 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.WeakSet.WeakSet 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.WeakSet.WeakSet.iterable_allowed Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.WeakSet.WeakSet.null_allowed Firefox3/31/2015 Edge7/29/2015120
javascript.builtins.WeakSet.add 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.WeakSet.delete 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.WeakSet.has 📋Firefox12/1/2014 Edge7/29/2015240
javascript.builtins.decodeURI 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.decodeURIComponent 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.encodeURI 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.encodeURIComponent 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.escape 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.eval 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.isFinite 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.isNaN 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.parseFloat 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.parseInt 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.parseInt.leading_zero_strings_as_decimal Firefox5/14/2013 Edge7/29/2015806
javascript.builtins.undefined 📋Firefox11/9/2004 Edge7/29/20153914
javascript.builtins.unescape 📋Firefox11/9/2004 Edge7/29/20153914
javascript.functions 📋Firefox11/9/2004 Edge7/29/20153914
javascript.functions.arguments 📋Firefox11/9/2004 Edge7/29/20153914
javascript.functions.arguments.callee 📋Firefox11/9/2004 Edge7/29/20153914
javascript.functions.arguments.length 📋Firefox11/9/2004 Edge7/29/20153914
javascript.functions.arrow_functions 📋Firefox6/25/2013 Edge7/29/2015764
Firefox: The initial implementation of arrow functions in Firefox made them automatically strict. This has been changed as of Firefox 24. The use of 'use strict'; is now required.Firefox: Before Firefox 39, a line terminator (\n) was incorrectly allowed after arrow function arguments. This has been fixed to conform to the ES2015 specification and code like () \n => {} will now throw a SyntaxError in this and later versions.Firefox for Android: The initial implementation of arrow functions in Firefox for Android made them automatically strict. This has been changed as of Firefox for Android 24. The use of 'use strict'; is now required.Firefox for Android: Before Firefox for Android 39, a line terminator (\n) was incorrectly allowed after arrow function arguments. This has been fixed to conform to the ES2015 specification and code like () \n => {} will now throw a SyntaxError in this and later versions.
javascript.functions.get 📋Firefox11/29/2005 Edge7/29/20153529
javascript.functions.get.computed_property_names Firefox12/1/2014 Edge7/29/2015240
javascript.functions.method_definitions 📋Firefox12/1/2014 Edge7/29/2015240
javascript.functions.rest_parameters 📋Firefox8/28/2012 Edge7/29/20151065
javascript.functions.set 📋Firefox11/29/2005 Edge7/29/20153529
javascript.functions.set.computed_property_names Firefox12/1/2014 Edge7/29/2015240
javascript.grammar.array_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.binary_numeric_literals 📋Firefox10/29/2013 Edge7/29/2015638
javascript.grammar.boolean_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.decimal_numeric_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.hexadecimal_escape_sequences 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.hexadecimal_numeric_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.null_literal 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.octal_numeric_literals 📋Firefox10/29/2013 Edge7/29/2015638
javascript.grammar.regular_expression_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.shorthand_object_literals Firefox10/14/2014 Edge7/29/2015288
javascript.grammar.string_literals 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.template_literals 📋Firefox12/1/2014 Edge7/29/2015240
javascript.grammar.trailing_commas 📋Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.trailing_commas.trailing_commas_in_object_literals Firefox11/9/2004 Edge7/29/20153914
javascript.grammar.unicode_escape_sequences 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.addition 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.addition_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_and 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_and_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_not 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_or 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_or_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_xor 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.bitwise_xor_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.comma 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.conditional 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.decrement 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.delete 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.division 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.division_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.equality 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.function 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.generator_function 📋Firefox12/10/2013 Edge7/29/2015596
javascript.operators.greater_than 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.greater_than_or_equal 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.grouping 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.in 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.increment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.inequality 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.instanceof 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.left_shift 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.left_shift_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.less_than 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.less_than_or_equal 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.logical_and 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.logical_not 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.logical_or 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.multiplication 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.multiplication_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.new 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.null 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.object_initializer 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.object_initializer.computed_property_names Firefox12/1/2014 Edge7/29/2015240
javascript.operators.object_initializer.shorthand_method_names Firefox12/1/2014 Edge7/29/2015240
javascript.operators.object_initializer.shorthand_property_names Firefox10/14/2014 Edge7/29/2015288
javascript.operators.property_accessors 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.remainder 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.remainder_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.right_shift 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.right_shift_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.spread 📋Firefox10/9/2012 Edge7/29/20151023
javascript.operators.spread.spread_in_arrays 📋Firefox10/9/2012 Edge7/29/20151023
javascript.operators.spread.spread_in_function_calls 📋Firefox2/4/2014 Edge7/29/2015540
javascript.operators.strict_equality 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.strict_inequality 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.subtraction 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.subtraction_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.this 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.typeof 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.unary_negation 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.unary_plus 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.unsigned_right_shift 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.unsigned_right_shift_assignment 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.void 📋Firefox11/9/2004 Edge7/29/20153914
javascript.operators.yield 📋Firefox12/10/2013 Edge7/29/2015596
Firefox: Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.Firefox: Starting with Firefox 29, an IteratorResult object returned for completed generator function.Firefox for Android: Starting with Firefox for Android 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.Firefox for Android: Starting with Firefox for Android 29, an IteratorResult object returned for completed generator function.
javascript.operators.yield_star 📋Firefox2/4/2014 Edge7/29/2015540
Firefox: Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.Firefox for Android: Starting with Firefox for Android 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.
javascript.regular_expressions.backreference 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.capturing_group 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.character_class 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.character_class_escape 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.character_escape 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.disjunction 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.input_boundary_assertion 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.literal_character 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.lookahead_assertion 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.non_capturing_group 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.quantifier 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.wildcard 📋Firefox11/9/2004 Edge7/29/20153914
javascript.regular_expressions.word_boundary_assertion 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.block 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.break 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.const 📋Firefox2/24/2015 Edge7/29/2015155
Firefox: Before Firefox 13, const is implemented, but re-assignment is not failing.Firefox: Before Firefox 46, a TypeError was thrown on redeclaration instead of a SyntaxError.Firefox for Android: Before Firefox for Android 14, const is implemented, but re-assignment is not failing.Firefox for Android: Before Firefox for Android 46, a TypeError was thrown on redeclaration instead of a SyntaxError.
javascript.statements.continue 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.debugger 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.do_while 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.empty 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.for 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.for_in 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.for_of 📋Firefox6/5/2012 Edge7/29/20151149
Firefox: Before Firefox 51, using the for...of loop construct with the const keyword threw a SyntaxError ("missing = in const declaration").Firefox for Android: Before Firefox for Android 51, using the for...of loop construct with the const keyword threw a SyntaxError ("missing = in const declaration").
javascript.statements.function 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.if_else 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.label 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.return 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.switch 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.throw 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.try_catch 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.var 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.while 📋Firefox11/9/2004 Edge7/29/20153914
javascript.statements.with 📋Firefox11/9/2004 Edge7/29/20153914