Firefox 85 release notes for developers

Changes for web developers

Developer Tools

• Developers can now use the Page Inspector to toggle the :focus-visible pseudo-class for the currently selected element (in addition to the pseudo classes that were previously supported: :hover, :active and :focus, :focus-within, and :visited). (Firefox bug 1617608).

HTML

• <link rel="preload"> is now enabled. (Firefox bug 1626997).

Removals

• The <menuitem> HTML element is no longer available — it has been hidden behind the dom.menuitem.enabled flag. (Firefox bug 1680596).

CSS

• The :focus-visible pseudo-class is now enabled. (Firefox bug 1445482).
• The pinch-zoom value for the touch-action property is now enabled. (Firefox bug 1329241).

JavaScript

• The collation property can now be specified in the options passed to the Intl.Collator() constructor (Firefox bug 1670062). This allows developers to write code with greater clarity:

  js

  // Old method
  let pinyin = new Intl.Collator(["zh-u-co-pinyin"]);
  // New method
  let pinyin = new Intl.Collator("zh", { collation: "pinyin" });
  

Plugins

• Flash support has been completely removed from Firefox (Firefox bug 1675349).

APIs

No changes.

WebDriver conformance (Marionette)

• Fixed a potential page load timeout situation when WebDriver:ElementClick is called for a link with a target other than _blank (Firefox bug 1678455).
• Using web element references on browsing contexts other than the originating one now correctly returns a no such element error instead of a stale element reference error (Firefox bug 1684827).

Known bugs

• WebDriver commands following a call to WebDriver:SwitchToFrame can fail with a "no such window" error if the frame's content hasn't yet finished loading (Firefox bug 1691348).
• After a cross-group page navigation, accessing a previously-retrieved element might not always raise a "stale element" error, and can also lead to a "no such element" error. To prevent this, set the marionette.actors.enabled preference to false (Firefox bug 1690308).

Changes for add-on developers

No changes.