This article provides information about the changes in Firefox 109 that will affect developers. Firefox 109 was released on January 17, 2023.

Changes for web developers

HTML

• Therange element supports thelist attribute, which links via an id to a<datalist> to allow Firefox to display tick marks along the range.

CSS

• The<system-color> CSS data type now supports the valuesMark,MarkText, andButtonBorder (Firefox bug 1638052).

JavaScript

No notable changes.

SVG

Removals

• SVGGraphicsElement.getTransformToElement() has been removed.This follows its removal from the SVG2 specification in 2015, and from other major browsers.(Firefox bug 1803790).

• TheSVGGraphicsElement.nearestViewportElement andSVGGraphicsElement.farthestViewportElement attributes have been disabled by default in nightly and early beta builds (behind preferencesvg.nearestAndFarthestViewportElement.enabled).SVGElement.viewportElement can be used as an alternative toSVGGraphicsElement.nearestViewportElement.They have been removed from the SVG2 specification and are likely to be removed entirely from Firefox in a future release.(Firefox bug 1133174).

HTTP

• The'unsafe-hashes' value forContent-Security-Policy source directives is now supported.For more information, seeCSP unsafe-hashes (Firefox bug 1343950).

APIs

DOM

• Thescrollend events are now supported, which indicate that the user has completed scrolling inElement andDocument objects.For more information, seeElement:scrollend event andDocument:scrollend event (Firefox bug 1797013,Firefox bug 1803435).

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

• The connection details for WebDriver BiDi are now written toWebDriverBiDiServer.json instead ofWebDriverBiDiActivePort, which contains both the port (ws_port) and the host (ws_host). This file is located in the Firefox profile folder (Firefox bug 1792875).
• Added support for subscribing / unsubscribing to individualcontexts when usingsession.subscribe andsession.unsubscribe (Firefox bug 1723102).
• Added support for serializingNode objects (Firefox bug 1770731).
• Fixed thecolumnNumber forexceptions andstackTraces to be 0-based (Firefox bug 1796073).

Marionette

• Fixed a bug whereWebDriver:NewWindow andWebDriver:SwitchToWindow were not focusing the new window properly (Firefox bug 1798655).
• Fixed a bug whereWebDriver:FindElement (and similar commands) would fail if the Firefox window was occluded by other applications on Windows (Firefox bug 1802473).

Changes for add-on developers

• Manifest V3 is now supported with the ability to sign and release Manifest V3 extensions on AMO. See theManifest v3 signing available November 21 on Firefox Nightly blog post for more information. The following preview features are now fully available:

  • Thescripting API, although this has been available to Manifest V2 extensions from Firefox 102.
  • Theaction API, and"action" manifest key and_execute_action special shortcut in the manifestcommands key.
  • The"host_permissions" manifest key.

• The defaultContent Security Policy (CSP) for Manifest V3 extensions has been updated toincludeupgrade-insecure-requests. This means that, by default, all network requests are upgraded to usehttps:. Extensions that need to usehttp: can do so by overriding the default CSP using thecontent_security_policy manifest.json key (Firefox bug 1797086).

• The propertysecretKeyLength has been added towebRequest.SecurityInfo. This property provides the length in bits of the secret key in the security properties of a web request (Firefox bug 1778473).

• With the introduction of theextensions button, the default value ofdefault_area in theaction andbrowser_action manifest keys has changed from"navbar" to"menupanel" (Firefox bug 1799947).

• Support foromnibox.onDeleteSuggestion and thedeletable property inomnibox.SuggestResult, enabling extensions to react to a user deleting an address bar search result (Firefox bug 1799947).

• Support for thetop andleft parameters to determine positioning ofpanel orpopup window usingwindows.create() (Firefox bug 1271047).