Firefox 134 for developers

Removals

• The align-self and justify-self CSS properties and place-self CSS shorthand property are now supported for absolutely positioned elements. (Firefox bug 1920160).

Removals

• Support for the RegExp.escape() static method that can be used to escape any potential regex syntax characters in a string, returning a new string that can be safely used as a literal pattern for the RegExp() constructor. (Firefox bug 1918235).
• The Promise.try() convenience method is now supported. The method takes a callback of any kind (a function that returns or throws, synchronously or asynchronously) and wraps its result in a Promise. This allows you to use promise semantics (.then(), .catch()) to handle the result from any kind of method. (Firefox bug 1917879 and Firefox bug 1905364).

Removals

Removals

Removals

Removals

• The PushManager.supportedContentEncodings static method is now supported for getting the allowed algorithms for encrypting the payload of a push message. (Firefox bug 1497430).
• AudioParam.value now allows the value to be set even during the time that an automated event is scheduled: previously the operation would silently be ignored at those times. (Firefox bug 1308435).
• The ReadableStreamBYOBReader.read() method has a new argument options.min that can be used to specify the minimum number of elements to be returned on each call. This might, for example, be used to avoid unnecessary iteration when working with data structures that have a known data size. (Firefox bug 1864406).

DOM

Media, WebRTC, and Web Audio

• WebRTC simulcast of screen-shared video with the VP8 codec is now supported (simulcast from other video sources has been enabled for a long time). More precisely, MediaStreamTrack objects for screen and window capture (for example, from MediaDevices.getDisplayMedia()), can now be encoded as multiple simulcast layers when using VP8. (Firefox bug 1692873).

Removals

Removals

General

WebDriver BiDi

Marionette

These features are newly shipped in Firefox 134 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config page and set it to true. You can find more such features on the Experimental features page.

• Intl.DurationFormat (Nightly release): Intl.DurationFormat enables locale-sensitive formatting of durations. (Firefox bug 1648139).
• autocorrect: dom.forms.autocorrect. The HTML autocorrect attribute and HTMLElement.autocorrect property allow autocorrection in editable text elements, including: most kinds of text <input> elements, <textarea> elements, and elements that have the contenteditable attribute set (Firefox bug 1725806).