Changes for web developers

HTML

No notable changes.

CSS

• The CSS Custom Highlight API is now supported. It provides a mechanism for styling arbitrary text ranges in a document, generalizing the behavior of other highlight pseudo-elements such as ::selection, ::spelling-error, ::grammar-error, and ::target-text. You define text ranges in JavaScript using Range instances that are grouped in a Highlight, and then register them with a name using HighlightRegistry. You can apply styles to a registered highlight using the CSS ::highlight pseudo-element. (Firefox bug 1964089).

Removals

• The UA styles for

  elements nested within sectioning elements have been removed, following the removal of the outline algorithm from the HTML specification. Previously, the

  headings nested within

  ,

JavaScript

No notable changes.

SVG

• The SVG fetchpriority attribute is now supported for the SVG , , and