This article provides information about the changes in Firefox 104 that will affect developers. Firefox 104 was released on August 23, 2022.

Changes for web developers

HTML

No notable changes.

CSS

No notable changes.

JavaScript

• The methodsArray.prototype.findLast(),Array.prototype.findLastIndex(),TypedArray.prototype.findLast(), andTypedArray.prototype.findLastIndex() are now supported.These are used to find the value and index (respectively) of the last element in anArray orTypedArray that matches a supplied test function.(SeeFirefox bug 1775026 for more details.)

• Serialization ofnative Error types additionally includes thestack property when used withwindow.postMessage() andstructuredClone() (on error types that includestack).Thestack is not yet serialized when errors are sent using other APIs, such asWorker.postMessage()(SeeFirefox bug 1774866 for more details.)

APIs

DOM

• HTMLElement.focus() now supports the parameteroption.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.(SeeFirefox bug 1765083 for more details.)

Canvas

• ThefontKerning property is now supported onCanvasRenderingContext2D andOffscreenCanvasRenderingContext2D, enabling developers to specify how kerning is used when text is drawn to a canvas or an offscreen canvas (Firefox bug 1778908).

SVG

• TheSVGStyleElement.disabled property can now be used to disable or enable an SVG style element, or to check its disabled state.This mirrors the behavior ofHTMLStyleElement.disabled.(SeeFirefox bug 1712623 for more details.)

Removals

• Theoptions argument to theIDBFactory.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 toStorageManager.persist().(SeeFirefox bug 1354500 for more details.)

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

• Added support forsource to thelog.entryAdded event (Firefox bug 1770792).
• Updated theurl sent forbrowsingContext.contextCreated events to beabout: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 fortouch actions (Firefox bug 1543337).

Changes for add-on developers

• Theemailtracking andemailtracking_content flags have been added to the tracking classifications available inurlClassification for thewebRequest events (Firefox bug 1773695)