Deprecated

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

Example Comparisons
Browsers
Features

Summary

A count of the number of APIs that were removed from A first and B last.
Last removed from FirefoxLast removed from Safari
First removed from Firefox 12
First removed from Safari 3

Average time for an API to be removed across Firefox and Safari

15 APIs took an average of 1636.80 days to be removed

API breakdown:

Average time to landing by year of first deprecation

If a feature is deprecated in the earliest browser in 20XX it took Y days on average to become deprecated in the last browser (when considering Firefox and Safari). TTA (time to available).
DOM API APIsDOM API TTACSS APIsCSS TTAHTML APIsHTML TTAJS APIsJS TTA
2012 14955.200NaN0NaN0NaN
2016 13555.200NaN0NaN0NaN
2017 13429.200NaN0NaN0NaN
2020 0NaN12148.2012274.200NaN
2021 11876.2021910.200NaN0NaN
2025 7356.200NaN0NaN0NaN

Deprecated APIs

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

Raw Data

Quick Links:

DOM API Data

API First Browser Date Last Browser Date Days Notes
api.CSSStyleDeclaration.cssFloat 📋Firefox11/20/2012 Safari9/15/2025
api.File.lastModifiedDate Safari9/20/2016 Firefox6/26/2018
api.MutationEvent Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.attrChange Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.attrName Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.initMutationEvent Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.newValue Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.prevValue Firefox6/24/2025 Safari9/15/2025
api.MutationEvent.relatedNode Firefox6/24/2025 Safari9/15/2025
api.RTCPeerConnection.removeStream Firefox1/24/2017 Safari9/17/2018
api.SpeechSynthesisEvent.elapsedTime.milliseconds Safari4/26/2021 Firefox12/7/2021
Firefox: Windows and macOS only.

CSS Data

API First Browser Date Last Browser Date Days Notes
css.at-rules.media.prefers-color-scheme.no-preference Firefox7/28/2020 Safari9/20/2021
css.properties.caption-side.left Firefox3/23/2021 Safari9/18/2023
css.properties.caption-side.right Firefox3/23/2021 Safari9/18/2023

HTML Data

API First Browser Date Last Browser Date Days Notes
html.elements.object.codebase 📋Safari3/24/2020 Firefox8/19/2025