DOMTokenList: supports() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.

The supports() method of the DOMTokenList interface returns true if a given token is in the associated attribute's supported tokens. This method is intended to support feature detection.

Syntax

js
supports(token)

Parameters

token

A string containing the token to query for.

Return value

A boolean value indicating whether the token was found.

Example

js
const iframe = document.getElementById("display");
if (iframe.sandbox.supports("an-upcoming-feature")) {
  // support code for mystery future feature
} else {
  // fallback code
}
if (iframe.sandbox.supports("allow-scripts")) {
  // instruct frame to run JavaScript
  //
  // (NOTE: This feature is well-supported; this is just an example!)
  //
}

Specifications

Specification
DOM
# ref-for-dom-domtokenlist-supports①

Browser compatibility