Firefox 104 release notes for developers

Changes for web developers

HTML

No notable changes.

CSS

No notable changes.

JavaScript

• The methods Array.prototype.findLast(), Array.prototype.findLastIndex(), TypedArray.prototype.findLast(), and TypedArray.prototype.findLastIndex() are now supported. These are used to find the value and index (respectively) of the last element in an Array or TypedArray that matches a supplied test function. (See Firefox bug 1775026 for more details.)

• Serialization of native Error types additionally includes the stack property when used with window.postMessage() and structuredClone() (on error types that include stack). The stack is not yet serialized when errors are sent using other APIs, such as Worker.postMessage() (See Firefox bug 1774866 for more details.)

APIs

DOM

• HTMLElement.focus() now supports the parameter option.focusVisible, which can be used force a browser to display visual indication after the element is focused. Note that browsers may automatically provide visual indication on focused elements if the implementation determines that it will improve accessibility. (See Firefox bug 1765083 for more details.)

Canvas

• The fontKerning property is now supported on CanvasRenderingContext2D and OffscreenCanvasRenderingContext2D, enabling developers to specify how kerning is used when text is drawn to a canvas or an offscreen canvas (Firefox bug 1778908).

SVG

• The SVGStyleElement.disabled property can now be used to disable or enable an SVG style element, or to check its disabled state. This mirrors the behavior of HTMLStyleElement.disabled. (See Firefox bug 1712623 for more details.)

Removals

• The options argument to the IDBFactory.open() method has been removed. This option provided a non-standard, and Firefox-only way to make the indicated database persistent. The option was previously deprecated, and users that need this functionality should already have migrated to StorageManager.persist(). (See Firefox bug 1354500 for more details.)

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

• Added support for source to the log.entryAdded event (Firefox bug 1770792).
• Updated the url sent for browsingContext.contextCreated events to be about:blank for newly opened browsing contexts (Firefox bug 1775141).

Marionette

• Improved stability and performance when minimizing or restoring windows on Linux (Firefox bug 1780212).
• Added support for touch actions (Firefox bug 1543337).

Changes for add-on developers

• The emailtracking and emailtracking_content flags have been added to the tracking classifications available in urlClassification for the webRequest events (Firefox bug 1773695)