Web platform features explorer

📃 July 2024 release notes

Newly available

The following features are newly available:

  • Alt text for generated content: The / notation in content CSS property values adds alternative text to generated content. For example, the content: url('upvote-icon.svg') / 'Upvote' declaration adds accessible 'Upvote' text to the SVG icon. Also known as alternate text.
  • font-size-adjust: The font-size-adjust CSS property preserves apparent text size, regardless of the font used, by scaling fonts to the same size with respect to a specific metric, such as x-height. This can help make fallback fonts look the same size.
  • Registered custom properties: The CSS.registerProperty() static method and the @property CSS at-rule register custom properties for which types and behaviors can be defined.
  • Resizable buffers: The resize() method of an ArrayBuffer and the grow() method of a SharedArrayBuffer, constructed with the maxByteLength option, changes the size of the buffer in place.

Widely available

The following features are now widely available:

  • font-synthesis: The font-synthesis CSS shorthand property disables all font synthesis except the given kinds. To disable a specific kind of font synthesis, instead use the longhand properties such as font-synthesis-style and font-synthesis-weight.

New in Firefox

The following features are now available in Firefox:

  • getHTML(): The getHTML() method of Element and ShadowRoot objects serializes an element's DOM to an HTML string.
  • Unsanitized HTML parsing methods: The Document.parseHTMLUnsafe() static method parses HTML into a DOM tree, while the setHTMLUnsafe() method of Element and ShadowRoot parses and inserts HTML into an existing tree. No sanitization applies to these methods, so never call them with user-provided HTML strings.
  • Relative colors: The from keyword for color functions (color(), hsl(), oklch(), etc.) creates a new color based on a given color by modifying the values of the input color. Also known as relative color syntax (RCS).

New in Firefox for Android

The following features are now available in Firefox for Android:

  • getHTML(): The getHTML() method of Element and ShadowRoot objects serializes an element's DOM to an HTML string.
  • Unsanitized HTML parsing methods: The Document.parseHTMLUnsafe() static method parses HTML into a DOM tree, while the setHTMLUnsafe() method of Element and ShadowRoot parses and inserts HTML into an existing tree. No sanitization applies to these methods, so never call them with user-provided HTML strings.
  • Relative colors: The from keyword for color functions (color(), hsl(), oklch(), etc.) creates a new color based on a given color by modifying the values of the input color. Also known as relative color syntax (RCS).