Time to Stable

For a given set of browsers, what APIs are in all of them and how many days it take for the API to land in the first browser to the last.

Example Comparisons

Summary

A count of the number of APIs that landed in A first and B last.
	Last in Firefox	Last in Safari
First in Firefox		593
First in Safari	478

Average time for an API to become available across Firefox and Safari

1071 APIs took an average of 522.37 days to become available to use.

API breakdown:

JS: 522.37 days

Average time to landing by year of first landing

If a feature landed in the earliest browser in 20XX it took Y days on average to become available in the last browser (when considering Firefox and Safari). TTA (time to available).
	JS APIs	JS TTA
2003	286	517.01
2004	32	1207.34
2005	13	1624.08
2008	4	1733.50
2009	5	150.00
2010	7	504.00
2011	84	624.25
2012	27	962.44
2013	70	791.21
2014	93	617.87
2015	80	389.81
2016	57	136.16
2017	33	356.88
2018	23	382.09
2019	34	505.32
2020	74	296.62
2021	45	409.36
2022	25	406.48
2023	40	448.25
2024	30	119.30
2025	9	70.11

The Tortoise and the Hare

There is a natural tension on the web with respect to browser engines. Every engine has their own set of priorities which define the level of investment that they choose to make and on which areas they choose to make it.

A developer naturally wants their experiences to be available to the widest audience possible and these differing priorities create an unevenness on the platform (a lumpiness) making it harder for developers to build experiences that work everywhere.

This section highlights where browsers are pushing and pulling on the platform.

Sprinters

This table is designed to show which browsers are pushing on the platform the most.

Adding features to quickly is not always desired because developers are unlikely to adopt those features in their sites or apps.

For a given year, if a feature landed in Browser X first, how many days it take on average to be available in Firefox and Safari. TTA (time to available).
Year	JS	JS TTA
2003
Safari	286	517.01
2004
Firefox	32	1207.34
2005
Firefox	9	696.00
Safari	4	3712.25
2008
Firefox	4	1733.50
2009
Safari	3	22.00
Firefox	2	342.00
2010
Safari	7	504.00
2011
Firefox	47	304.47
Safari	37	1030.46
2012
Firefox	24	985.46
Safari	3	778.33
2013
Firefox	59	750.31
Safari	11	1010.64
2014
Firefox	90	632.32
Safari	3	184.33
2015
Firefox	72	402.79
Safari	8	273.00
2016
Firefox	31	108.94
Safari	26	168.62
2017
Firefox	30	351.77
Safari	3	408.00
2018
Firefox	17	294.00
Safari	6	631.67
2019
Firefox	32	533.31
Safari	2	57.50
2020
Firefox	73	299.73
Safari	1	70.00
2021
Firefox	28	139.54
Safari	17	853.76
2022
Firefox	2	289.50
Safari	23	416.65
2023
Safari	34	508.09
Firefox	6	109.17
2024
Firefox	28	125.89
Safari	2	27.00
2025
Safari	2	15.00
Firefox	7	85.86

Plodders

This table is designed to show which browsers are pulling on the platform the most.

For a feature that first landed in year X, how many days did it take on average for the last browser to catch up across Firefox and Safari. TTA (time to available).
Year	JS count	JS TTA
2003
Firefox	286	517.01
2004
Safari	32	1207.34
2005
Safari	9	696.00
Firefox	4	3712.25
2008
Safari	4	1733.50
2009
Firefox	3	22.00
Safari	2	342.00
2010
Firefox	7	504.00
2011
Safari	47	304.47
Firefox	37	1030.46
2012
Safari	24	985.46
Firefox	3	778.33
2013
Safari	59	750.31
Firefox	11	1010.64
2014
Safari	90	632.32
Firefox	3	184.33
2015
Safari	72	402.79
Firefox	8	273.00
2016
Safari	31	108.94
Firefox	26	168.62
2017
Safari	30	351.77
Firefox	3	408.00
2018
Safari	17	294.00
Firefox	6	631.67
2019
Safari	32	533.31
Firefox	2	57.50
2020
Safari	73	299.73
Firefox	1	70.00
2021
Safari	28	139.54
Firefox	17	853.76
2022
Safari	2	289.50
Firefox	23	416.65
2023
Firefox	34	508.09
Safari	6	109.17
2024
Safari	28	125.89
Firefox	2	27.00
2025
Firefox	2	15.00
Safari	7	85.86

Stable APIs

Below is a list of features that are in Firefox and Safari

Raw Data

Quick Links:

JS Data

API	First Browser	Date	Last Browser	Date	Days	Notes
javascript.builtins.AggregateError 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.builtins.AggregateError.AggregateError 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.builtins.AggregateError.errors 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.builtins.AggregateError.serializable_object	Firefox	7/26/2022	Safari	9/18/2023	419	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.Array 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.@@iterator 📋	Firefox	2/24/2015	Safari	9/20/2016	574	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.@@species 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.Array.@@unscopables 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.Array.Array 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.at 📋	Firefox	7/13/2021	Safari	3/14/2022	244
javascript.builtins.Array.concat 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.copyWithin 📋	Firefox	9/2/2014	Safari	9/30/2015	393
javascript.builtins.Array.entries 📋	Firefox	3/18/2014	Safari	10/16/2014	212
javascript.builtins.Array.every 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.fill 📋	Firefox	7/22/2014	Safari	10/16/2014	86
javascript.builtins.Array.filter 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.find 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Array.findIndex 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Array.findLast 📋	Safari	3/14/2022	Firefox	8/23/2022	162
javascript.builtins.Array.findLastIndex 📋	Safari	3/14/2022	Firefox	8/23/2022	162
javascript.builtins.Array.flat 📋	Firefox	9/5/2018	Safari	9/17/2018	12
javascript.builtins.Array.flatMap 📋	Firefox	9/5/2018	Safari	9/17/2018	12
javascript.builtins.Array.forEach 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.from 📋	Firefox	9/2/2014	Safari	9/30/2015	393
javascript.builtins.Array.fromAsync 📋	Safari	3/27/2023	Firefox	7/4/2023	99
javascript.builtins.Array.includes 📋	Safari	9/30/2015	Firefox	12/15/2015	76
javascript.builtins.Array.indexOf 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.isArray 📋	Safari	6/7/2010	Firefox	3/22/2011	288
javascript.builtins.Array.join 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.keys 📋	Firefox	3/18/2014	Safari	10/16/2014	212
javascript.builtins.Array.lastIndexOf 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.length 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.map 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.of 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.builtins.Array.pop 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.push 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.reduce 📋	Firefox	6/17/2008	Safari	6/8/2009	356
javascript.builtins.Array.reduceRight 📋	Firefox	6/17/2008	Safari	6/8/2009	356
javascript.builtins.Array.reverse 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.shift 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.slice 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.some 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.builtins.Array.sort 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.sort.stable_sorting	Firefox	6/17/2008	Safari	3/27/2017	3205
javascript.builtins.Array.splice 📋	Safari	6/23/2003	Firefox	11/9/2004	505	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 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.toLocaleString.locales_parameter	Safari	10/22/2013	Firefox	3/7/2017	1232	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	Safari	10/22/2013	Firefox	3/7/2017	1232
javascript.builtins.Array.toReversed 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.Array.toSorted 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.Array.toSpliced 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.Array.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.unshift 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Array.values 📋	Safari	9/30/2015	Firefox	5/9/2018	952
javascript.builtins.Array.with 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.ArrayBuffer 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.ArrayBuffer.@@species 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.ArrayBuffer.ArrayBuffer 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.ArrayBuffer.ArrayBuffer.maxByteLength_option 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.ArrayBuffer.byteLength 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.ArrayBuffer.detached 📋	Firefox	1/23/2024	Safari	3/5/2024	42
javascript.builtins.ArrayBuffer.isView 📋	Safari	10/22/2013	Firefox	4/29/2014	189
javascript.builtins.ArrayBuffer.maxByteLength 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.ArrayBuffer.resizable 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.ArrayBuffer.resize 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.ArrayBuffer.slice 📋	Safari	7/20/2011	Firefox	4/24/2012	279	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.ArrayBuffer.transfer 📋	Firefox	1/23/2024	Safari	3/5/2024	42
javascript.builtins.ArrayBuffer.transferToFixedLength 📋	Firefox	1/23/2024	Safari	3/5/2024	42
javascript.builtins.AsyncFunction 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.builtins.AsyncFunction.AsyncFunction 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.builtins.AsyncGenerator 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncGenerator.next 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncGenerator.return 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncGenerator.throw 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncGeneratorFunction 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncGeneratorFunction.AsyncGeneratorFunction 📋	Firefox	8/8/2017	Safari	9/17/2018	405
javascript.builtins.AsyncIterator 📋	Firefox	11/14/2017	Safari	4/12/2018	149
javascript.builtins.AsyncIterator.@@asyncIterator 📋	Firefox	11/14/2017	Safari	4/12/2018	149
javascript.builtins.Atomics 📋	Firefox	6/30/2020	Safari	12/13/2021	531	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 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.and 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.compareExchange 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.exchange 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.isLockFree 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.load 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.notify 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.or 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.pause 📋	Safari	3/31/2025	Firefox	4/1/2025	1
javascript.builtins.Atomics.store 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.sub 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.wait 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.Atomics.waitAsync 📋	Safari	3/27/2023	Firefox	11/11/2025	960	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.
javascript.builtins.Atomics.xor 📋	Firefox	6/30/2020	Safari	12/13/2021	531
javascript.builtins.BigInt 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.BigInt 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.asIntN 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.asUintN 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.toLocaleString 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.toLocaleString.locales_parameter	Firefox	10/22/2019	Safari	9/16/2020	330	Deno: Only the locale data for `en-US` is available.
javascript.builtins.BigInt.toLocaleString.options_parameter	Firefox	10/22/2019	Safari	9/16/2020	330
javascript.builtins.BigInt.toString 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt.valueOf 📋	Firefox	7/9/2019	Safari	9/16/2020	435
javascript.builtins.BigInt64Array 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.BigInt64Array.BigInt64Array 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.BigUint64Array 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.BigUint64Array.BigUint64Array 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.Boolean 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Boolean.Boolean 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Boolean.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Boolean.valueOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.DataView 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.DataView 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.DataView.sharedarraybuffer_support	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.DataView.buffer 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.byteLength 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.byteOffset 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getBigInt64 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.DataView.getBigUint64 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.DataView.getFloat16 📋	Firefox	8/6/2024	Safari	12/11/2024	127
javascript.builtins.DataView.getFloat32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getFloat64 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getInt16 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getInt32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getInt8 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getUint16 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getUint32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.getUint8 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setBigInt64 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.DataView.setBigUint64 📋	Firefox	7/9/2019	Safari	9/20/2021	804
javascript.builtins.DataView.setFloat16 📋	Firefox	8/6/2024	Safari	12/11/2024	127
javascript.builtins.DataView.setFloat32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setFloat64 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setInt16 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setInt32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setInt8 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setUint16 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setUint32 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.DataView.setUint8 📋	Safari	7/20/2011	Firefox	8/28/2012	405
javascript.builtins.Date 📋	Safari	6/23/2003	Firefox	11/9/2004	505	Internet Explorer: The ISO8601 Date Format is not supported in Internet Explorer 8 or earlier.
javascript.builtins.Date.@@toPrimitive 📋	Firefox	1/26/2016	Safari	9/20/2016	238
javascript.builtins.Date.Date 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.UTC 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.UTC.optional_monthIndex	Firefox	3/22/2011	Safari	3/27/2017	2197
javascript.builtins.Date.getDate 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getDay 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getFullYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getHours 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getMilliseconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getMinutes 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getMonth 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getSeconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getTime 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getTimezoneOffset 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCDate 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCDay 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCFullYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCHours 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCMilliseconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCMinutes 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCMonth 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getUTCSeconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.getYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.now 📋	Firefox	11/9/2004	Safari	6/8/2009	1672
javascript.builtins.Date.parse 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.parse.iso_8601	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Date.setDate 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setFullYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setHours 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setMilliseconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setMinutes 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setMonth 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setSeconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setTime 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCDate 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCFullYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCHours 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCMilliseconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCMinutes 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCMonth 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setUTCSeconds 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.setYear 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toDateString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toGMTString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toISOString 📋	Firefox	11/9/2004	Safari	6/8/2009	1672
javascript.builtins.Date.toJSON 📋	Firefox	11/9/2004	Safari	6/8/2009	1672
javascript.builtins.Date.toLocaleDateString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toLocaleDateString.iana_time_zone_names	Safari	10/22/2013	Firefox	3/7/2017	1232
javascript.builtins.Date.toLocaleDateString.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Date.toLocaleString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toLocaleString.iana_time_zone_names	Safari	10/22/2013	Firefox	3/7/2017	1232
javascript.builtins.Date.toLocaleString.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Date.toLocaleTimeString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toLocaleTimeString.iana_time_zone_names	Safari	10/22/2013	Firefox	3/7/2017	1232
javascript.builtins.Date.toLocaleTimeString.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Date.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toTimeString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.toUTCString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Date.valueOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Error 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Error.Error 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Error.Error.options_cause_parameter 📋	Firefox	8/10/2021	Safari	9/20/2021	41
javascript.builtins.Error.captureStackTrace 📋	Safari	12/11/2023	Firefox	4/29/2025	505
javascript.builtins.Error.cause 📋	Firefox	8/10/2021	Safari	9/20/2021	41	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.
javascript.builtins.Error.isError 📋	Safari	3/31/2025	Firefox	4/29/2025	29	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.builtins.Error.message 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Error.name 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Error.stack	Firefox	11/9/2004	Safari	7/25/2012	2815
javascript.builtins.Error.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.EvalError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.EvalError.EvalError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.FinalizationRegistry 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.FinalizationRegistry.FinalizationRegistry 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.FinalizationRegistry.register 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.FinalizationRegistry.register.symbol_as_target	Safari	3/27/2023	Firefox	12/9/2025	988
javascript.builtins.FinalizationRegistry.unregister 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.Float16Array 📋	Firefox	8/6/2024	Safari	12/11/2024	127
javascript.builtins.Float16Array.Float16Array 📋	Firefox	8/6/2024	Safari	12/11/2024	127
javascript.builtins.Float32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Float32Array.Float32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Float32Array.Float32Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Float32Array.Float32Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Float64Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Float64Array.Float64Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Float64Array.Float64Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Float64Array.Float64Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Function 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.@@hasInstance 📋	Safari	9/20/2016	Firefox	11/15/2016	56
javascript.builtins.Function.Function 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.apply 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.apply.generic_arrays_as_arguments	Firefox	3/22/2011	Safari	7/25/2012	491
javascript.builtins.Function.arguments	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.bind 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Function.call 📋	Safari	6/23/2003	Firefox	11/9/2004	505	Node.js: When calling this method, `thisArg` does not default to the global object.
javascript.builtins.Function.caller	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Function.length 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.length.configurable_true	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.Function.name 📋	Firefox	11/9/2004	Safari	7/25/2012	2815
javascript.builtins.Function.name.configurable_true	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.Function.name.inferred_names	Safari	9/20/2016	Firefox	4/19/2017	211	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 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Function.toString.toString_revision	Firefox	6/13/2017	Safari	9/18/2023	2288
javascript.builtins.Generator 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.builtins.Generator.next 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.builtins.Generator.return 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.Generator.throw 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.builtins.GeneratorFunction 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.builtins.GeneratorFunction.GeneratorFunction 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.builtins.Infinity 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Int16Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int16Array.Int16Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int16Array.Int16Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Int16Array.Int16Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Int32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int32Array.Int32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int32Array.Int32Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Int32Array.Int32Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Int8Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int8Array.Int8Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Int8Array.Int8Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Int8Array.Int8Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Intl 📋	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.Collator.options_caseFirst_parameter	Firefox	8/8/2017	Safari	9/19/2017	42
javascript.builtins.Intl.Collator.Collator.options_collation_parameter	Firefox	1/26/2021	Safari	4/26/2021	90
javascript.builtins.Intl.Collator.Collator.options_ignorePunctuation_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator.Collator.options_localeMatcher_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator.Collator.options_numeric_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator.Collator.options_sensitivity_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator.Collator.options_usage_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.Collator.compare 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.IntlLegacyConstructedSymbol 📋	Firefox	6/13/2017	Safari	4/26/2021	1413	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.DateTimeFormat.DateTimeFormat.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_calendar_parameter	Firefox	5/5/2020	Safari	4/26/2021	356
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_dateStyle_parameter	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_dayPeriod_parameter	Safari	4/26/2021	Firefox	7/13/2021	78
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_fractionalSecondDigits_parameter	Firefox	12/15/2020	Safari	4/26/2021	132
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_hourCycle_parameter	Firefox	1/23/2018	Safari	9/19/2019	604
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_numberingSystem_parameter	Firefox	5/5/2020	Safari	4/26/2021	356
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeStyle_parameter	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZoneName_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZoneName_parameter.extended_values	Firefox	8/10/2021	Safari	3/14/2022	216
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZone_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.DateTimeFormat.DateTimeFormat.options_parameter.options_timeZone_parameter.iana_time_zones	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Intl.DateTimeFormat.format 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.formatRange 📋	Safari	4/26/2021	Firefox	8/10/2021	106	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 📋	Safari	4/26/2021	Firefox	8/10/2021	106	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.formatToParts 📋	Firefox	1/24/2017	Safari	9/19/2017	238	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.DateTimeFormat.resolvedOptions 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.computed_timezone	Safari	9/20/2016	Firefox	4/19/2017	211
javascript.builtins.Intl.DateTimeFormat.supportedLocalesOf 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.DisplayNames 📋	Firefox	2/23/2021	Safari	4/26/2021	62
javascript.builtins.Intl.DisplayNames.DisplayNames 📋	Firefox	2/23/2021	Safari	4/26/2021	62
javascript.builtins.Intl.DisplayNames.of 📋	Firefox	2/23/2021	Safari	4/26/2021	62
javascript.builtins.Intl.DisplayNames.resolvedOptions 📋	Firefox	2/23/2021	Safari	4/26/2021	62
javascript.builtins.Intl.DisplayNames.supportedLocalesOf 📋	Firefox	2/23/2021	Safari	4/26/2021	62
javascript.builtins.Intl.DurationFormat 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.DurationFormat.DurationFormat 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.DurationFormat.format 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.DurationFormat.formatToParts 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.DurationFormat.resolvedOptions 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.DurationFormat.supportedLocalesOf 📋	Safari	3/27/2023	Firefox	3/4/2025	708
javascript.builtins.Intl.ListFormat 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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 📋	Firefox	6/30/2020	Safari	4/26/2021	300	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.Locale 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.Locale 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.baseName 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.calendar 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.caseFirst 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.collation 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.hourCycle 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.language 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.maximize 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.minimize 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.numberingSystem 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.numeric 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.region 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.script 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.toString 📋	Firefox	4/7/2020	Safari	9/16/2020	162
javascript.builtins.Intl.Locale.variants 📋	Firefox	7/22/2025	Safari	9/15/2025	55
javascript.builtins.Intl.NumberFormat 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.IntlLegacyConstructedSymbol 📋	Firefox	6/13/2017	Safari	4/26/2021	1413	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.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_compactDisplay_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_currencyDisplay_parameter	Firefox	11/3/2015	Safari	4/26/2021	2001	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.NumberFormat.NumberFormat.options_parameter.options_currencySign_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_currency_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_localeMatcher_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_maximumFractionDigits_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_maximumSignificantDigits_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumFractionDigits_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumIntegerDigits_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_minimumSignificantDigits_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_notation_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_numberingSystem_parameter	Firefox	5/5/2020	Safari	4/26/2021	356
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingIncrement_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingMode_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_roundingPriority_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_signDisplay_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_signDisplay_parameter.negative	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_style_parameter	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_trailingZeroDisplay_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_unitDisplay_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_unit_parameter	Firefox	6/30/2020	Safari	4/26/2021	300
javascript.builtins.Intl.NumberFormat.NumberFormat.options_parameter.options_useGrouping_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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.options_useGrouping_parameter.string_values	Safari	3/27/2023	Firefox	8/1/2023	127
javascript.builtins.Intl.NumberFormat.format 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.format.number_parameter-string_decimal	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.formatRange 📋	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.formatRangeToParts 📋	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.NumberFormat.formatToParts 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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 📋	Firefox	4/29/2014	Safari	9/20/2016	875	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.PluralRules 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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.PluralRules.options_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter.options_roundingIncrement_parameter	Firefox	8/1/2023	Safari	12/11/2023	132
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter.options_roundingMode_parameter	Firefox	8/1/2023	Safari	12/11/2023	132
javascript.builtins.Intl.PluralRules.PluralRules.options_parameter.options_roundingPriority_parameter	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.PluralRules.resolvedOptions 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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.selectRange 📋	Safari	3/14/2022	Firefox	8/1/2023	505
javascript.builtins.Intl.PluralRules.supportedLocalesOf 📋	Firefox	1/23/2018	Safari	9/19/2019	604	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.RelativeTimeFormat 📋	Firefox	1/29/2019	Safari	9/16/2020	596	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 📋	Firefox	1/29/2019	Safari	9/16/2020	596
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.locales_parameter	Firefox	1/29/2019	Safari	9/16/2020	596	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	Firefox	1/29/2019	Safari	9/16/2020	596
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.options_parameter.options_numberingSystem_parameter	Firefox	5/5/2020	Safari	9/16/2020	134
javascript.builtins.Intl.RelativeTimeFormat.RelativeTimeFormat.options_parameter.options_numeric_parameter	Firefox	1/29/2019	Safari	9/16/2020	596
javascript.builtins.Intl.RelativeTimeFormat.format 📋	Firefox	1/29/2019	Safari	9/16/2020	596	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 📋	Firefox	10/22/2019	Safari	9/16/2020	330	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 📋	Firefox	1/29/2019	Safari	9/16/2020	596	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 📋	Firefox	1/29/2019	Safari	9/16/2020	596	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.Segmenter 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segmenter.Segmenter 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segmenter.resolvedOptions 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segmenter.segment 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segmenter.supportedLocalesOf 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segments 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segments.@@iterator 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.Segments.containing 📋	Safari	4/26/2021	Firefox	4/16/2024	1086
javascript.builtins.Intl.getCanonicalLocales 📋	Firefox	8/2/2016	Safari	3/27/2017	237
javascript.builtins.Intl.supportedValuesOf 📋	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_calendar	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_collation	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_currency	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_numberingSystem	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_timeZone	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_timeZone.includes_UTC	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Intl.supportedValuesOf.key_parameter_unit	Firefox	10/5/2021	Safari	3/14/2022	160
javascript.builtins.Iterator 📋	Firefox	11/20/2012	Safari	9/20/2016	1400
javascript.builtins.Iterator.@@iterator 📋	Firefox	2/24/2015	Safari	9/20/2016	574	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.Iterator.Iterator 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.drop 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.every 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.filter 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.find 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.flatMap 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.forEach 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.from 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.map 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.reduce 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.some 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.take 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.Iterator.toArray 📋	Firefox	10/1/2024	Safari	3/31/2025	181
javascript.builtins.JSON 📋	Safari	6/8/2009	Firefox	6/30/2009	22
javascript.builtins.JSON.json_superset	Firefox	9/5/2018	Safari	9/17/2018	12
javascript.builtins.JSON.parse 📋	Safari	6/8/2009	Firefox	6/30/2009	22
javascript.builtins.JSON.parse.reviver_parameter_context_argument 📋	Firefox	2/4/2025	Safari	3/31/2025	55
javascript.builtins.JSON.stringify 📋	Safari	6/8/2009	Firefox	6/30/2009	22
javascript.builtins.JSON.stringify.well_formed_stringify	Firefox	12/11/2018	Safari	3/25/2019	104
javascript.builtins.Map 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Map.@@iterator 📋	Firefox	2/24/2015	Safari	9/20/2016	574	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.@@species 📋	Firefox	9/22/2015	Safari	9/20/2016	364
javascript.builtins.Map.Map 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Map.Map.iterable_allowed	Firefox	6/5/2012	Safari	9/30/2015	1212
javascript.builtins.Map.Map.null_allowed	Firefox	3/31/2015	Safari	9/30/2015	183
javascript.builtins.Map.clear 📋	Firefox	2/19/2013	Safari	10/16/2014	604
javascript.builtins.Map.delete 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Map.entries 📋	Firefox	4/2/2013	Safari	10/16/2014	562
javascript.builtins.Map.forEach 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Map.get 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Map.getOrInsert 📋	Firefox	10/14/2025	Safari	12/12/2025	59
javascript.builtins.Map.getOrInsertComputed 📋	Firefox	10/14/2025	Safari	12/12/2025	59
javascript.builtins.Map.groupBy 📋	Firefox	10/24/2023	Safari	3/5/2024	133
javascript.builtins.Map.has 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Map.key_equality_for_zeros	Firefox	4/29/2014	Safari	9/30/2015	519
javascript.builtins.Map.keys 📋	Firefox	4/2/2013	Safari	10/16/2014	562
javascript.builtins.Map.set 📋	Firefox	6/5/2012	Safari	10/16/2014	863	Internet Explorer: Returns 'undefined' instead of the 'Map' object.
javascript.builtins.Map.size 📋	Firefox	2/19/2013	Safari	10/16/2014	604	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 📋	Firefox	4/2/2013	Safari	10/16/2014	562
javascript.builtins.Math 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.E 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.LN10 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.LN2 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.LOG10E 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.LOG2E 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.PI 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.SQRT1_2 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.SQRT2 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.abs 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.acos 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.acosh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.asin 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.asinh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.atan 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.atan2 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.atanh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.cbrt 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.ceil 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.clz32 📋	Safari	10/22/2013	Firefox	7/22/2014	273
javascript.builtins.Math.cos 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.cosh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.exp 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.expm1 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.f16round 📋	Firefox	8/6/2024	Safari	12/11/2024	127
javascript.builtins.Math.floor 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.fround 📋	Firefox	12/10/2013	Safari	10/16/2014	310
javascript.builtins.Math.hypot 📋	Firefox	2/4/2014	Safari	10/16/2014	254
javascript.builtins.Math.imul 📋	Firefox	4/2/2013	Safari	10/22/2013	203
javascript.builtins.Math.log 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.log10 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.log1p 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.log2 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.max 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.min 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.pow 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.random 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.round 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.sign 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.builtins.Math.sin 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.sinh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.sqrt 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.sumPrecise 📋	Firefox	4/1/2025	Safari	12/12/2025	255
javascript.builtins.Math.tan 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Math.tanh 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Math.trunc 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.NaN 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.EPSILON 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.builtins.Number.MAX_SAFE_INTEGER 📋	Firefox	7/22/2014	Safari	9/30/2015	435
javascript.builtins.Number.MAX_VALUE 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.MIN_SAFE_INTEGER 📋	Firefox	7/22/2014	Safari	9/30/2015	435
javascript.builtins.Number.MIN_VALUE 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.NEGATIVE_INFINITY 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.NaN 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.Number 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.POSITIVE_INFINITY 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.isFinite 📋	Firefox	10/9/2012	Safari	9/30/2015	1086
javascript.builtins.Number.isInteger 📋	Firefox	10/9/2012	Safari	9/30/2015	1086
javascript.builtins.Number.isNaN 📋	Firefox	8/28/2012	Safari	9/30/2015	1128
javascript.builtins.Number.isSafeInteger 📋	Firefox	9/2/2014	Safari	9/30/2015	393
javascript.builtins.Number.parseFloat 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.builtins.Number.parseInt 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.builtins.Number.toExponential 📋	Firefox	11/9/2004	Safari	4/29/2005	171
javascript.builtins.Number.toFixed 📋	Firefox	11/9/2004	Safari	4/29/2005	171
javascript.builtins.Number.toLocaleString 📋	Safari	6/23/2003	Firefox	11/9/2004	505	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	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.Number.toPrecision 📋	Firefox	11/9/2004	Safari	4/29/2005	171
javascript.builtins.Number.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Number.valueOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.Object 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.assign 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.Object.constructor 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.create 📋	Safari	6/7/2010	Firefox	3/22/2011	288
javascript.builtins.Object.defineGetter 📋	Firefox	11/9/2004	Safari	10/26/2007	1081	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 📋	Safari	6/7/2010	Firefox	3/22/2011	288
javascript.builtins.Object.defineProperty 📋	Firefox	3/22/2011	Safari	7/20/2011	120	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 📋	Firefox	11/9/2004	Safari	10/26/2007	1081	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.entries 📋	Firefox	6/7/2016	Safari	3/27/2017	293
javascript.builtins.Object.freeze 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.fromEntries 📋	Firefox	10/23/2018	Safari	3/25/2019	153
javascript.builtins.Object.getOwnPropertyDescriptor 📋	Safari	6/7/2010	Firefox	3/22/2011	288	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.getOwnPropertyDescriptors 📋	Safari	9/20/2016	Firefox	11/15/2016	56
javascript.builtins.Object.getOwnPropertyNames 📋	Safari	6/7/2010	Firefox	3/22/2011	288
javascript.builtins.Object.getOwnPropertySymbols 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.Object.getPrototypeOf 📋	Firefox	6/30/2009	Safari	6/7/2010	342
javascript.builtins.Object.groupBy 📋	Firefox	10/24/2023	Safari	3/5/2024	133
javascript.builtins.Object.hasOwn 📋	Firefox	9/7/2021	Safari	3/14/2022	188
javascript.builtins.Object.hasOwnProperty 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.is 📋	Firefox	6/25/2013	Safari	9/30/2015	827
javascript.builtins.Object.isExtensible 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.isFrozen 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.isPrototypeOf 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.isSealed 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.keys 📋	Safari	6/7/2010	Firefox	3/22/2011	288
javascript.builtins.Object.lookupGetter 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.lookupSetter 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.preventExtensions 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.preventExtensions.ES2015_behavior	Firefox	1/13/2015	Safari	9/30/2015	260
javascript.builtins.Object.propertyIsEnumerable 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.proto 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.Object.seal 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Object.setPrototypeOf 📋	Firefox	7/22/2014	Safari	9/30/2015	435
javascript.builtins.Object.toLocaleString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.valueOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Object.values 📋	Firefox	6/7/2016	Safari	3/27/2017	293
javascript.builtins.Promise 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.@@species 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.Promise.Promise 📋	Firefox	4/29/2014	Safari	10/16/2014	170	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 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.allSettled 📋	Safari	9/19/2019	Firefox	12/10/2019	82
javascript.builtins.Promise.any 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.builtins.Promise.catch 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.finally 📋	Firefox	1/23/2018	Safari	4/12/2018	79
javascript.builtins.Promise.race 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.reject 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.resolve 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.then 📋	Firefox	4/29/2014	Safari	10/16/2014	170
javascript.builtins.Promise.try 📋	Safari	12/11/2024	Firefox	1/7/2025	27
javascript.builtins.Promise.withResolvers 📋	Firefox	12/19/2023	Safari	3/5/2024	77
javascript.builtins.Proxy 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.Proxy 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.apply 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.construct 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.defineProperty 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.deleteProperty 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.get 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.getOwnPropertyDescriptor 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.getPrototypeOf 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.Proxy.handler.has 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.isExtensible 📋	Firefox	7/22/2014	Safari	9/20/2016	791
javascript.builtins.Proxy.handler.ownKeys 📋	Firefox	1/8/2013	Safari	9/20/2016	1351	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 📋	Firefox	6/25/2013	Safari	9/20/2016	1183
javascript.builtins.Proxy.handler.set 📋	Firefox	1/8/2013	Safari	9/20/2016	1351
javascript.builtins.Proxy.handler.setPrototypeOf 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.Proxy.revocable 📋	Firefox	12/1/2014	Safari	9/20/2016	659
javascript.builtins.RangeError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RangeError.RangeError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.ReferenceError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.ReferenceError.ReferenceError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Reflect 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.apply 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.construct 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.defineProperty 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.deleteProperty 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.get 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.getOwnPropertyDescriptor 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.getPrototypeOf 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.has 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.isExtensible 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.ownKeys 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.preventExtensions 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.set 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.Reflect.setPrototypeOf 📋	Firefox	11/3/2015	Safari	9/20/2016	322
javascript.builtins.RegExp 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.@@match 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.RegExp.@@matchAll 📋	Firefox	5/21/2019	Safari	9/19/2019	121
javascript.builtins.RegExp.@@replace 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.RegExp.@@search 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.RegExp.@@species 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.RegExp.@@split 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.RegExp.RegExp 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.compile 📋	Firefox	11/9/2004	Safari	3/18/2008	1225
javascript.builtins.RegExp.compile.rexexp_legacy_features	Safari	7/20/2022	Firefox	2/24/2026	1315
javascript.builtins.RegExp.dotAll 📋	Safari	4/12/2018	Firefox	6/30/2020	810
javascript.builtins.RegExp.escape 📋	Safari	12/11/2024	Firefox	1/7/2025	27
javascript.builtins.RegExp.exec 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.flags 📋	Firefox	3/31/2015	Safari	9/30/2015	183
javascript.builtins.RegExp.global 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.global.prototype_accessor	Safari	4/15/2005	Firefox	5/12/2015	3679
javascript.builtins.RegExp.hasIndices 📋	Firefox	4/19/2021	Safari	9/20/2021	154
javascript.builtins.RegExp.ignoreCase 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.ignoreCase.prototype_accessor	Safari	4/15/2005	Firefox	5/12/2015	3679
javascript.builtins.RegExp.input 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.RegExp.lastIndex 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.lastMatch 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.RegExp.lastParen 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.RegExp.leftContext 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.RegExp.multiline 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.multiline.prototype_accessor	Safari	4/15/2005	Firefox	5/12/2015	3679
javascript.builtins.RegExp.n 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.rightContext 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.RegExp.source 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.source.empty_regex_string	Safari	6/7/2010	Firefox	5/12/2015	1800
javascript.builtins.RegExp.source.escaping	Safari	7/25/2012	Firefox	5/12/2015	1021
javascript.builtins.RegExp.source.prototype_accessor	Safari	4/15/2005	Firefox	9/22/2015	3812
javascript.builtins.RegExp.sticky 📋	Firefox	6/17/2008	Safari	9/20/2016	3017
javascript.builtins.RegExp.sticky.anchored_sticky_flag	Firefox	1/26/2016	Safari	9/20/2016	238
javascript.builtins.RegExp.sticky.prototype_accessor	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.RegExp.test 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.RegExp.toString.escaping	Safari	7/25/2012	Firefox	5/12/2015	1021
javascript.builtins.RegExp.unicode 📋	Firefox	4/26/2016	Safari	9/20/2016	147	Edge: Case folding is implemented in version 13Node.js: Case folding is implemented in version 8.6.0
javascript.builtins.RegExp.unicodeSets 📋	Firefox	8/1/2023	Safari	9/18/2023	48
javascript.builtins.Set 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Set.@@iterator 📋	Firefox	2/24/2015	Safari	9/30/2015	218	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.@@species 📋	Firefox	9/22/2015	Safari	9/20/2016	364
javascript.builtins.Set.Set 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Set.Set.iterable_allowed	Firefox	6/5/2012	Safari	9/30/2015	1212
javascript.builtins.Set.Set.null_allowed	Firefox	3/31/2015	Safari	9/30/2015	183
javascript.builtins.Set.add 📋	Firefox	6/5/2012	Safari	10/16/2014	863	Internet Explorer: Returns 'undefined' instead of the 'Set' object.
javascript.builtins.Set.clear 📋	Firefox	2/19/2013	Safari	10/16/2014	604
javascript.builtins.Set.delete 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Set.difference 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.entries 📋	Firefox	9/17/2013	Safari	10/16/2014	394
javascript.builtins.Set.forEach 📋	Firefox	10/29/2013	Safari	10/16/2014	352
javascript.builtins.Set.has 📋	Firefox	6/5/2012	Safari	10/16/2014	863
javascript.builtins.Set.intersection 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.isDisjointFrom 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.isSubsetOf 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.isSupersetOf 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.key_equality_for_zeros	Firefox	4/29/2014	Safari	9/30/2015	519
javascript.builtins.Set.keys 📋	Firefox	9/17/2013	Safari	10/16/2014	394
javascript.builtins.Set.size 📋	Firefox	2/19/2013	Safari	10/16/2014	604	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.symmetricDifference 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.union 📋	Safari	9/18/2023	Firefox	6/11/2024	267
javascript.builtins.Set.values 📋	Firefox	9/17/2013	Safari	10/16/2014	394
javascript.builtins.SharedArrayBuffer 📋	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.SharedArrayBuffer.@@species 📋	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.SharedArrayBuffer.SharedArrayBuffer 📋	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.SharedArrayBuffer.SharedArrayBuffer.maxByteLength_option 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.SharedArrayBuffer.byteLength 📋	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.SharedArrayBuffer.grow 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.SharedArrayBuffer.growable 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.SharedArrayBuffer.maxByteLength 📋	Safari	3/27/2023	Firefox	7/9/2024	470
javascript.builtins.SharedArrayBuffer.slice 📋	Firefox	7/28/2020	Safari	12/13/2021	503
javascript.builtins.String 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.@@iterator 📋	Firefox	2/24/2015	Safari	9/30/2015	218	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 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.anchor 📋	Safari	6/23/2003	Firefox	11/9/2004	505	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.at 📋	Firefox	7/13/2021	Safari	3/14/2022	244
javascript.builtins.String.big 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.blink 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.bold 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.charAt 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.charCodeAt 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.codePointAt 📋	Firefox	4/29/2014	Safari	9/30/2015	519
javascript.builtins.String.concat 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.endsWith 📋	Firefox	11/20/2012	Safari	9/30/2015	1044
javascript.builtins.String.fixed 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.fontcolor 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.fontsize 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.fromCharCode 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.fromCodePoint 📋	Firefox	4/29/2014	Safari	9/30/2015	519
javascript.builtins.String.includes 📋	Firefox	8/11/2015	Safari	9/30/2015	50
javascript.builtins.String.indexOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.isWellFormed 📋	Safari	3/27/2023	Firefox	10/24/2023	211
javascript.builtins.String.italics 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.lastIndexOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.length 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.link 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.localeCompare 📋	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.builtins.String.localeCompare.locales_parameter	Firefox	4/29/2014	Safari	9/20/2016	875	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	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.builtins.String.match 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.matchAll 📋	Firefox	5/21/2019	Safari	9/19/2019	121
javascript.builtins.String.normalize 📋	Firefox	7/22/2014	Safari	9/20/2016	791
javascript.builtins.String.padEnd 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.String.padStart 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.String.raw 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.String.repeat 📋	Firefox	9/17/2013	Safari	9/30/2015	743
javascript.builtins.String.replace 📋	Safari	6/23/2003	Firefox	11/9/2004	505	Internet Explorer: A replacement function as second argument is not supported.
javascript.builtins.String.replaceAll 📋	Safari	3/24/2020	Firefox	6/2/2020	70
javascript.builtins.String.search 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.slice 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.small 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.split 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.startsWith 📋	Firefox	11/20/2012	Safari	9/30/2015	1044
javascript.builtins.String.strike 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.sub 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.substr 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.substring 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.sup 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.toLocaleLowerCase 📋	Firefox	11/9/2004	Safari	4/15/2005	157
javascript.builtins.String.toLocaleLowerCase.locales_parameter	Safari	9/20/2016	Firefox	8/8/2017	322	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 📋	Firefox	11/9/2004	Safari	4/15/2005	157
javascript.builtins.String.toLocaleUpperCase.locales_parameter	Safari	9/20/2016	Firefox	8/8/2017	322	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.toLowerCase 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.toString 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.toUpperCase 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.String.toWellFormed 📋	Safari	3/27/2023	Firefox	10/24/2023	211
javascript.builtins.String.trim 📋	Firefox	6/30/2009	Safari	6/7/2010	342
javascript.builtins.String.trimEnd 📋	Firefox	6/26/2018	Safari	9/17/2018	83
javascript.builtins.String.trimStart 📋	Firefox	6/26/2018	Safari	9/17/2018	83
javascript.builtins.String.unicode_code_point_escapes	Safari	6/23/2003	Firefox	8/11/2015	4432
javascript.builtins.String.valueOf 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Symbol 📋	Firefox	2/24/2015	Safari	9/30/2015	218	Edge: Edge 12 included Symbol properties in `JSON.stringify()` output.
javascript.builtins.Symbol.@@toPrimitive 📋	Firefox	1/26/2016	Safari	9/20/2016	238
javascript.builtins.Symbol.Symbol 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.Symbol.asyncIterator 📋	Firefox	11/14/2017	Safari	4/12/2018	149
javascript.builtins.Symbol.description 📋	Firefox	10/23/2018	Safari	3/25/2019	153	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.for 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.Symbol.hasInstance 📋	Safari	9/20/2016	Firefox	11/15/2016	56
javascript.builtins.Symbol.isConcatSpreadable 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.Symbol.iterator 📋	Firefox	2/24/2015	Safari	9/20/2016	574
javascript.builtins.Symbol.keyFor 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.Symbol.match 📋	Firefox	8/11/2015	Safari	9/20/2016	406
javascript.builtins.Symbol.matchAll 📋	Firefox	5/21/2019	Safari	9/19/2019	121
javascript.builtins.Symbol.replace 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.Symbol.search 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.Symbol.species 📋	Firefox	9/22/2015	Safari	9/20/2016	364
javascript.builtins.Symbol.split 📋	Firefox	9/20/2016	Safari	9/20/2016
javascript.builtins.Symbol.toPrimitive 📋	Firefox	1/26/2016	Safari	9/20/2016	238
javascript.builtins.Symbol.toString 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.Symbol.toStringTag 📋	Safari	9/20/2016	Firefox	1/24/2017	126
javascript.builtins.Symbol.toStringTag.dom_objects	Firefox	6/30/2020	Safari	9/16/2020	78
javascript.builtins.Symbol.unscopables 📋	Safari	9/30/2015	Firefox	8/2/2016	307
javascript.builtins.Symbol.valueOf 📋	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.SyntaxError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.SyntaxError.SyntaxError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.TypeError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.TypeError.TypeError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.TypedArray 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.@@iterator 📋	Firefox	2/24/2015	Safari	9/20/2016	574	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.@@species 📋	Firefox	8/2/2016	Safari	9/20/2016	49
javascript.builtins.TypedArray.BYTES_PER_ELEMENT 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.at 📋	Firefox	7/13/2021	Safari	3/14/2022	244
javascript.builtins.TypedArray.buffer 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.byteLength 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.byteOffset 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.TypedArray.copyWithin 📋	Firefox	12/1/2014	Safari	9/20/2016	659
javascript.builtins.TypedArray.entries 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.every 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.fill 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.filter 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.find 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.findIndex 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.findLast 📋	Safari	3/14/2022	Firefox	8/23/2022	162
javascript.builtins.TypedArray.findLastIndex 📋	Safari	3/14/2022	Firefox	8/23/2022	162
javascript.builtins.TypedArray.forEach 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.from 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.includes 📋	Firefox	12/15/2015	Safari	9/20/2016	280
javascript.builtins.TypedArray.indexOf 📋	Firefox	3/31/2015	Safari	9/20/2016	539	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	Safari	7/20/2011	Firefox	10/29/2013	832	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.iterable_in_constructor	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.TypedArray.join 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.keys 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.lastIndexOf 📋	Firefox	3/31/2015	Safari	9/20/2016	539	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 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.map 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.name 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.named_properties	Safari	7/20/2011	Firefox	6/10/2014	1056
javascript.builtins.TypedArray.of 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.reduce 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.reduceRight 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.reverse 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.set 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.slice 📋	Firefox	5/12/2015	Safari	9/20/2016	497
javascript.builtins.TypedArray.some 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.sort 📋	Firefox	4/26/2016	Safari	9/20/2016	147
javascript.builtins.TypedArray.subarray 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.TypedArray.toLocaleString 📋	Safari	7/20/2011	Firefox	1/24/2017	2015
javascript.builtins.TypedArray.toReversed 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.TypedArray.toSorted 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.TypedArray.toString 📋	Safari	7/20/2011	Firefox	1/24/2017	2015
javascript.builtins.TypedArray.values 📋	Firefox	3/31/2015	Safari	9/20/2016	539
javascript.builtins.TypedArray.with 📋	Safari	9/12/2022	Firefox	7/4/2023	295
javascript.builtins.URIError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.URIError.URIError 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.Uint16Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint16Array.Uint16Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint16Array.Uint16Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Uint16Array.Uint16Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Uint32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint32Array.Uint32Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint32Array.Uint32Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Uint32Array.Uint32Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Uint8Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint8Array.Uint8Array 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint8Array.Uint8Array.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Uint8Array.Uint8Array.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.Uint8Array.fromBase64 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8Array.fromHex 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8Array.setFromBase64 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8Array.setFromHex 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8Array.toBase64 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8Array.toHex 📋	Firefox	11/26/2024	Safari	12/11/2024	15
javascript.builtins.Uint8ClampedArray 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray 📋	Firefox	3/22/2011	Safari	7/20/2011	120
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray.constructor_without_parameters	Safari	7/20/2011	Firefox	8/8/2017	2211
javascript.builtins.Uint8ClampedArray.Uint8ClampedArray.iterable_allowed	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.builtins.WeakMap 📋	Firefox	8/16/2011	Safari	10/16/2014	1157
javascript.builtins.WeakMap.WeakMap 📋	Firefox	8/16/2011	Safari	10/16/2014	1157
javascript.builtins.WeakMap.WeakMap.iterable_allowed	Firefox	2/24/2015	Safari	9/30/2015	218
javascript.builtins.WeakMap.WeakMap.null_allowed	Safari	10/16/2014	Firefox	3/31/2015	166
javascript.builtins.WeakMap.delete 📋	Firefox	8/16/2011	Safari	10/16/2014	1157	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 📋	Firefox	8/16/2011	Safari	10/16/2014	1157	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.getOrInsert 📋	Firefox	10/14/2025	Safari	12/12/2025	59
javascript.builtins.WeakMap.getOrInsertComputed 📋	Firefox	10/14/2025	Safari	12/12/2025	59
javascript.builtins.WeakMap.has 📋	Firefox	8/16/2011	Safari	10/16/2014	1157	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 📋	Firefox	8/16/2011	Safari	10/16/2014	1157	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.WeakMap.symbol_as_keys	Safari	3/27/2023	Firefox	12/9/2025	988
javascript.builtins.WeakRef 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.WeakRef.WeakRef 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.WeakRef.WeakRef.symbol_as_target	Safari	3/27/2023	Firefox	12/9/2025	988
javascript.builtins.WeakRef.deref 📋	Firefox	7/28/2020	Safari	4/26/2021	272
javascript.builtins.WeakSet 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.WeakSet 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.WeakSet.iterable_allowed	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.WeakSet.null_allowed	Firefox	3/31/2015	Safari	9/30/2015	183
javascript.builtins.WeakSet.add 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.delete 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.has 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.builtins.WeakSet.symbol_as_keys	Safari	3/27/2023	Firefox	12/9/2025	988
javascript.builtins.decodeURI 📋	Safari	10/24/2003	Firefox	11/9/2004	382
javascript.builtins.decodeURIComponent 📋	Safari	10/24/2003	Firefox	11/9/2004	382
javascript.builtins.encodeURI 📋	Safari	10/24/2003	Firefox	11/9/2004	382
javascript.builtins.encodeURIComponent 📋	Safari	10/24/2003	Firefox	11/9/2004	382
javascript.builtins.escape 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.eval 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.globalThis 📋	Firefox	1/29/2019	Safari	3/25/2019	55
javascript.builtins.isFinite 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.isNaN 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.parseFloat 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.parseInt 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.parseInt.leading_zero_strings_as_decimal	Safari	7/25/2012	Firefox	5/14/2013	293
javascript.builtins.undefined 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.builtins.unescape 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.classes 📋	Safari	9/30/2015	Firefox	3/8/2016	160	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 📋	Safari	9/30/2015	Firefox	3/8/2016	160	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 📋	Safari	9/30/2015	Firefox	3/8/2016	160	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.private_class_fields 📋	Safari	4/26/2021	Firefox	7/13/2021	78
javascript.classes.private_class_fields_in 📋	Firefox	7/13/2021	Safari	9/20/2021	69
javascript.classes.private_class_methods 📋	Firefox	7/13/2021	Safari	9/20/2021	69
javascript.classes.public_class_fields 📋	Firefox	9/3/2019	Safari	9/12/2022	1105	Safari: Parentheses in field initializers can lead to `ReferenceError`s. See bug 236843.Safari: Doesn't support public static fields. See bug 194095.Safari on iOS: Parentheses in field initializers can lead to `ReferenceError`s. 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 `ReferenceError`s. See bug 236843.WebView on iOS: Doesn't support public static fields. See bug 194095.
javascript.classes.static 📋	Safari	9/30/2015	Firefox	3/8/2016	160	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.class_fields 📋	Firefox	4/7/2020	Safari	4/26/2021	384
javascript.classes.static.initialization_blocks 📋	Firefox	10/5/2021	Safari	3/27/2023	538
javascript.functions 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.functions.arguments 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.functions.arguments.@@iterator 📋	Safari	9/30/2015	Firefox	4/26/2016	209
javascript.functions.arguments.callee 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.functions.arguments.length 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.functions.arrow_functions 📋	Firefox	6/25/2013	Safari	9/20/2016	1183	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.arrow_functions.trailing_comma	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.functions.block_level_functions	Firefox	4/26/2016	Safari	9/20/2016	147
javascript.functions.default_parameters 📋	Firefox	8/28/2012	Safari	9/20/2016	1484
javascript.functions.default_parameters.destructured_parameter_with_default_value_assignment	Firefox	9/22/2015	Safari	9/20/2016	364
javascript.functions.default_parameters.parameters_without_defaults_after_default_parameters	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.functions.get 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.functions.get.computed_property_names	Firefox	12/1/2014	Safari	3/21/2016	476
javascript.functions.method_definitions 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.functions.method_definitions.async_generator_methods	Firefox	11/14/2017	Safari	9/17/2018	307
javascript.functions.method_definitions.async_methods	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.functions.method_definitions.generator_methods_not_constructable	Firefox	12/15/2015	Safari	3/21/2016	97
javascript.functions.rest_parameters 📋	Firefox	8/28/2012	Safari	9/20/2016	1484
javascript.functions.rest_parameters.destructuring	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.functions.set 📋	Firefox	11/29/2005	Safari	10/26/2007	696
javascript.functions.set.computed_property_names	Firefox	12/1/2014	Safari	3/21/2016	476
javascript.grammar.array_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.binary_numeric_literals 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.grammar.boolean_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.decimal_numeric_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.hashbang_comments 📋	Firefox	5/21/2019	Safari	3/24/2020	308
javascript.grammar.hexadecimal_escape_sequences 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.hexadecimal_numeric_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.null_literal 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.numeric_separators 📋	Safari	9/19/2019	Firefox	10/22/2019	33
javascript.grammar.octal_numeric_literals 📋	Firefox	10/29/2013	Safari	9/30/2015	701
javascript.grammar.regular_expression_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.shorthand_object_literals	Firefox	10/14/2014	Safari	9/30/2015	351
javascript.grammar.string_literals 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.template_literals 📋	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.grammar.template_literals.template_literal_revision	Firefox	4/19/2017	Safari	9/19/2017	153
javascript.grammar.trailing_commas 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.trailing_commas.trailing_commas_in_dynamic_import 📋	Safari	9/20/2021	Firefox	4/29/2025	1317	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.grammar.trailing_commas.trailing_commas_in_functions	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.grammar.trailing_commas.trailing_commas_in_object_literals	Firefox	11/9/2004	Safari	10/26/2007	1081
javascript.grammar.unicode_escape_sequences 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.grammar.unicode_point_escapes 📋	Firefox	8/11/2015	Safari	9/30/2015	50
javascript.operators.addition 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.addition_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.async_function 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.operators.async_generator_function 📋	Firefox	11/14/2017	Safari	9/17/2018	307
javascript.operators.await 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.operators.await.top_level 📋	Firefox	6/1/2021	Safari	9/20/2021	111	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).
javascript.operators.bitwise_and 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_and_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_not 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_or 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_or_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_xor 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.bitwise_xor_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.class 📋	Safari	10/22/2013	Firefox	3/8/2016	868
javascript.operators.comma 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.conditional 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.decrement 📋	Firefox	11/9/2004	Safari	6/8/2009	1672
javascript.operators.delete 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.destructuring 📋	Safari	10/16/2014	Firefox	9/22/2015	341	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	Firefox	9/22/2015	Safari	9/20/2016	364
javascript.operators.destructuring.rest_in_arrays	Firefox	9/22/2015	Safari	3/21/2016	181
javascript.operators.destructuring.rest_in_objects	Firefox	8/8/2017	Safari	4/12/2018	247
javascript.operators.division 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.division_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.equality 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.exponentiation 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.operators.exponentiation_assignment 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.operators.function 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.function.trailing_comma	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.operators.generator_function 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.operators.generator_function.trailing_comma	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.operators.greater_than 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.greater_than_or_equal 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.grouping 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.import 📋	Safari	4/12/2018	Firefox	5/21/2019	404	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.options_parameter 📋	Safari	9/20/2021	Firefox	4/29/2025	1317	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.worker_support	Safari	9/20/2021	Firefox	6/6/2023	624
javascript.operators.import_meta 📋	Safari	4/12/2018	Firefox	9/5/2018	146
javascript.operators.import_meta.resolve 📋	Firefox	10/18/2022	Safari	3/27/2023	160	Node.js: Returns a `URL` object instead of a string.
javascript.operators.in 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.increment 📋	Firefox	11/9/2004	Safari	6/8/2009	1672
javascript.operators.inequality 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.instanceof 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.left_shift 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.left_shift_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.less_than 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.less_than_or_equal 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.logical_and 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.logical_and_assignment 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.operators.logical_not 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.logical_or 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.logical_or_assignment 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.operators.multiplication 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.multiplication_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.new 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.new_target 📋	Firefox	9/22/2015	Safari	9/19/2017	728
javascript.operators.null 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.nullish_coalescing 📋	Firefox	1/7/2020	Safari	3/24/2020	77
javascript.operators.nullish_coalescing_assignment 📋	Firefox	7/28/2020	Safari	9/16/2020	50
javascript.operators.object_initializer 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.object_initializer.computed_property_names	Safari	10/16/2014	Firefox	12/1/2014	46
javascript.operators.object_initializer.shorthand_method_names	Firefox	12/1/2014	Safari	9/30/2015	303
javascript.operators.object_initializer.shorthand_property_names	Firefox	10/14/2014	Safari	9/30/2015	351
javascript.operators.object_initializer.spread_properties	Firefox	8/8/2017	Safari	4/12/2018	247
javascript.operators.optional_chaining 📋	Firefox	3/10/2020	Safari	3/24/2020	14
javascript.operators.property_accessors 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.remainder 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.remainder_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.right_shift 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.right_shift_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.spread 📋	Firefox	10/9/2012	Safari	10/16/2014	737
javascript.operators.spread.spread_in_arrays 📋	Firefox	10/9/2012	Safari	10/16/2014	737
javascript.operators.spread.spread_in_function_calls 📋	Firefox	2/4/2014	Safari	10/16/2014	254
javascript.operators.spread.spread_in_object_literals 📋	Firefox	8/8/2017	Safari	4/12/2018	247
javascript.operators.strict_equality 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.strict_inequality 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.subtraction 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.subtraction_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.super 📋	Safari	10/22/2013	Firefox	3/8/2016	868
javascript.operators.this 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.typeof 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.unary_negation 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.unary_plus 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.unsigned_right_shift 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.unsigned_right_shift_assignment 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.operators.void 📋	Firefox	11/9/2004	Safari	3/18/2008	1225
javascript.operators.yield 📋	Firefox	12/10/2013	Safari	9/20/2016	1015	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 📋	Firefox	2/4/2014	Safari	9/20/2016	959	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 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.capturing_group 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.character_class 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.character_class_escape 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.character_escape 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.character_escape.unicode	Firefox	4/26/2016	Safari	9/20/2016	147
javascript.regular_expressions.disjunction 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.input_boundary_assertion 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.literal_character 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.lookahead_assertion 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.lookbehind_assertion 📋	Firefox	6/30/2020	Safari	3/27/2023	1000
javascript.regular_expressions.modifier 📋	Firefox	10/29/2024	Safari	9/15/2025	321
javascript.regular_expressions.named_backreference 📋	Safari	4/12/2018	Firefox	6/30/2020	810
javascript.regular_expressions.named_capturing_group 📋	Safari	4/12/2018	Firefox	6/30/2020	810
javascript.regular_expressions.named_capturing_group.duplicate_named_capturing_groups	Safari	9/18/2023	Firefox	8/6/2024	323
javascript.regular_expressions.non_capturing_group 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.quantifier 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.unicode_character_class_escape 📋	Safari	4/12/2018	Firefox	6/30/2020	810
javascript.regular_expressions.wildcard 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.regular_expressions.word_boundary_assertion 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.async_function 📋	Firefox	3/7/2017	Safari	3/27/2017	20
javascript.statements.async_generator_function 📋	Firefox	11/14/2017	Safari	9/17/2018	307
javascript.statements.block 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.break 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.class 📋	Firefox	3/8/2016	Safari	3/27/2017	384	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.statements.const 📋	Safari	7/20/2011	Firefox	2/24/2015	1315	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 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.debugger 📋	Firefox	11/9/2004	Safari	6/7/2010	2036
javascript.statements.do_while 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.empty 📋	Firefox	11/9/2004	Safari	6/7/2010	2036
javascript.statements.export 📋	Safari	3/27/2017	Firefox	5/9/2018	408	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.arbitrary_module_namespace_identifier_names	Firefox	3/23/2021	Safari	4/26/2021	34
javascript.statements.export.default 📋	Safari	3/27/2017	Firefox	5/9/2018	408	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.namespace 📋	Firefox	8/25/2020	Safari	4/26/2021	244	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.for 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.for_await_of 📋	Firefox	11/14/2017	Safari	9/17/2018	307
javascript.statements.for_in 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.for_of 📋	Firefox	6/5/2012	Safari	10/22/2013	504	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.for_of.async_iterators	Safari	10/22/2013	Firefox	11/14/2017	1484
javascript.statements.for_of.closing_iterators	Safari	10/22/2013	Firefox	4/19/2017	1275
javascript.statements.function 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.function.trailing_comma_in_parameters	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.statements.generator_function 📋	Firefox	12/10/2013	Safari	9/20/2016	1015
javascript.statements.generator_function.IteratorResult_object	Firefox	4/29/2014	Safari	9/20/2016	875
javascript.statements.generator_function.not_constructable_with_new	Firefox	12/15/2015	Safari	9/20/2016	280
javascript.statements.generator_function.trailing_comma_in_parameters	Safari	9/20/2016	Firefox	3/7/2017	168
javascript.statements.if_else 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.import 📋	Safari	3/27/2017	Firefox	5/9/2018	408	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.
javascript.statements.import.arbitrary_module_namespace_identifier_names	Firefox	3/23/2021	Safari	4/26/2021	34
javascript.statements.import.import_attributes 📋	Safari	12/11/2023	Firefox	4/29/2025	505
javascript.statements.import.import_attributes.type_json	Safari	12/11/2023	Firefox	4/29/2025	505
javascript.statements.import.service_worker_support	Safari	9/20/2021	Firefox	1/13/2026	1576
javascript.statements.import.worker_support	Safari	9/20/2021	Firefox	6/6/2023	624
javascript.statements.label 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.let 📋	Firefox	1/26/2016	Safari	9/20/2016	238	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.
javascript.statements.return 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.switch 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.throw 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.try_catch 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.try_catch.optional_catch_binding	Firefox	1/23/2018	Safari	4/12/2018	79
javascript.statements.var 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.while 📋	Safari	6/23/2003	Firefox	11/9/2004	505
javascript.statements.with 📋	Safari	6/23/2003	Firefox	11/9/2004	505