Firefox 131 for developers

Removals

Removals

Removals

Removals

• A Set-Cookie HTTP header with the attribute value of SameSite=None must now also include the Secure attribute. This ensures that cookies set with SameSite=None are only ever sent over HTTPS channels. (Firefox bug 1909673).
• Cookies Having Independent Partitioned State (CHIPS), or "partitioned cookies", are now supported. This feature allow developers to opt a cookie into partitioned storage using the partitioned directive of the Set-Cookie HTTP header. When set, cookies have separate storage for each top-level site, and can only be read within the same top-level site they were set on and its subdomains. This blocks cross-site tracking, while still enabling legitimate uses of third-party cookies such as persisting state of embedded maps or chat widgets across different subdomains of a site. (Firefox bug 1908160).

Removals

Removals

• The altitudeAngle and azimuthAngle properties of the PointerEvent interface are supported, providing the angle between the pointer/stylus and the screen (X-Y plane), and the rotation of the stylus over the screen relative to its x-axis, respectively. (Firefox bug 1656377).
• Text fragments are now supported, allowing users to link to and highlight specific portions of text in a web page. This feature uses a particular syntax in the URL fragment that identifies the target based on patterns in the rendered text. Website developers can also use the existence of the Document.fragmentDirective property (an instance of the FragmentDirective interface) to feature check for text fragment support, and the ::target-text pseudo element to select and style text that has been selected using a text fragment link. (Firefox bug 1914877)

DOM

Media, WebRTC, and Web Audio

Removals

Removals

General

WebDriver BiDi

Marionette

These features are newly shipped in Firefox 131 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.

• Regular expression (?ims-ims:...) modifiers: javascript.options.experimental.regexp_modifiers The (?ims-ims:...) regular expression modifiers allow you to make changes to only take effect in a specific part of a regex pattern. (Firefox bug 1899813).
• Permissions for microphone and camera: permissions.media.query.enabled The microphone and camera permissions can now be used in the Permissions.query() method to test whether access to the corresponding hardware have been granted, denied, or still requires user approval (Firefox bug 1609427, Firefox bug 1915222).