Firefox 143 for developers

Changes for web developers

CSS

• The ::details-content pseudo-element is now enabled by default. It lets you style the content of the <details> element. (Firefox bug 1941406).
• Multi-pass grid track sizing is now enabled by default and follows the algorithm outlined in the CSS Grid specification. In the multi-pass algorithm, columns are sized first, then rows; percentage values are resolved after the container size is known. With this default support, percentage-based row tracks and grid items with aspect ratios will now be sized correctly in more cases. (Firefox bug 1957244).

APIs

Removals

• The deprecated CompositionEvent.locale property is no longer supported. (Firefox bug 1700969).

Changes for add-on developers

• Addition of storage.StorageArea.getKeys(). This method returns an array containing all of the keys in a storage area. It's available for all storage areas, that is sync, local, session, and managed. (Firefox bug 1910669)
• User selection of an extension suggestion in the address bar (omnibox), an action that fires omnibox.onInputEntered, is now considered a user action. In addition to enabling the APIs that require a user action, selecting an extension suggestion in the address bar also grants the "activeTab" permission.

Experimental web features

• text-autospace: layout.css.text-autospace.enabled

  The text-autospace CSS property allows you to specify the space applied between Chinese/Japanese/Korean (CJK) and non-CJK characters. Currently these values are only parsed and there is no effect on the output. (Firefox bug 1869577).

These features are shipping in Firefox 143 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config page and set it to true. You can find more such features on the Experimental features page.