Firefox 89 for developers

No changes.

No changes.

• The forced-colors media feature has been implemented (Firefox bug 1659511).
• The ascent-override, descent-override, and line-gap-override @font-face descriptors have been implemented (Firefox bug 1681691 and Firefox bug 1704494).
• The type() function for image-set() has been implemented (Firefox bug 1695404).
• The aspect-ratio CSS property is now supported (Firefox bug 1672073).

• Top-level await is now enabled by default (Firefox bug 1681046).
• ArrayBuffers can now be created with a length greater than 2GB-1 (up to 8GB) on 64-bit systems (Firefox bug 1703505).

No changes.

DOM

• PerformanceEventTiming is now enabled by default (Firefox bug 1701029).
• The content of <input> and <textarea> elements can now be manipulated using Document.execCommand() commands by default, preserving edit history and providing parity with other browsers, without contentEditable or any lengthy workarounds required (Firefox bug 1220696).

Removals

• The following sensor events and their associated handlers have been removed (primarily for better compatibility with other major browser engines, and to address concerns related to privacy leaks):

  • DeviceProximityEvent and its event handler window.ondeviceproximity (Firefox bug 1699707).
  • UserProximityEvent and its event handler window.onuserproximity) (Firefox bug 1699707).
  • DeviceLightEvent and its event handler window.ondevicelight (Firefox bug 1701824).

Removals

• The rotatable capability that is not part of the WebDriver specification is no longer used (Firefox bug 1697630).

• Dynamic JS module imports are now working in WebExtension content scripts (Firefox bug 1536094).
• Extension resources listed in web_accessible_resources can be loaded regardless of the request's CORS mode (Firefox bug 1694679).
• Firefox's UI has been redesigned, which affects usage of the theme API. The tab_background_separator and toolbar_field_separator properties are no longer supported. The tab_line and toolbar_vertical_separator will behave differently. For more information, see Changes to themeable areas of Firefox in version 89.
• The pageAction button can no longer be pinned or unpinned from the address bar, because the three-dot meatball menu is no longer visible by default (Firefox bug 1691454). As a result, the pinned property of the page_action manifest key no longer has any effect (Firefox bug 1703537).
• The "Remove from Address Bar" context menu item has been removed from the pageAction button (Firefox bug 1704474). For alternatives to this functionality, see Firefox bug 1712556.