Highlight: add() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The add() method of the Highlight interface adds a new Range object to a highlight, to be styled using the CSS Custom Highlight API.

Highlight is a Set-like object, so this is similar to using Set.add().

Syntax

js
add(range)

Parameters

range

A Range object to add to the Highlight.

Return value

The Highlight object, with the added range.

Examples

The code snippet below shows how to add two ranges to a new highlight object:

js
const highlight = new Highlight();

const range1 = new Range();
const range2 = new Range();

highlight.add(range1).add(range2);

console.log(highlight.size); // 2

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-set.prototype.add

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
add

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
See implementation notes.

See also