Firefox 105 for developers

Changes for web developers

HTML

No notable changes.

CSS

• Embedded content, such as SVG definitions and content in an <iframe>, now respects the theme preferences of the elements in which it is embedded, rather than OS or browser preferences (which may be different). Specifically, embedded content now inherits the color-scheme of the embedding element, and prefers-color-scheme media queries in the embedded content respect this value rather than the OS/browser level theme setting (Firefox bug 1779457).

JavaScript

• Range restrictions have been relaxed on formatRange and selectRange functions for Intl.DateTimeFormat, Intl.NumberFormat, and Intl.PluralRules objects. This change now allows negative ranges (Firefox bug 1780545).

APIs

DOM

• The TextDecoderStream and TextEncoderStream interfaces, part of the Encoding API, are now supported (Firefox bug 1486949).

• The OffscreenCanvas API provides a canvas that can be rendered off-screen in both window and web worker contexts. This allows <canvas> elements to be decoupled from the DOM. The OffscreenCanvasRenderingContext2D interface provides support for this and is now enabled by default (Firefox bug 1779009).

• The CSS Font Loading API can now be used in worker threads (Firefox bug 1072107).

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

• On systems with IPv6 preferred DNS resolution clients will no longer fail to connect when localhost is used as host for the WebSocket server (Firefox bug 1769994).

• Improved RemoteValue support to allow plain JS objects with simple JSON-serializable fields to be serialized (Firefox bug 1779226).

Marionette

• The WebDriver:GetElementProperty command is now able to return node properties as set by web content (Firefox bug 1398792).

Changes for add-on developers

• Support for defining persistent scripts using scripting has been added. A script is identified as persistent using the persistAcrossSessions property in scripting.RegisteredContentScript (Firefox bug 1751436).
• An extension's resources can no longer be loaded by other extensions by default. To enable other extensions to load resources they must be listed in the extension's web_accessible_resources manifest key (Firefox bug 1711168).