DOMTokenList: contains() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The contains() method of the DOMTokenList interface returns a boolean value — true if the underlying list contains the given token, otherwise false.

Syntax

js
contains(token)

Parameters

token

A string representing the token you want to check for the existence of in the list.

Return value

A boolean value, which is true if the calling list contains token, otherwise false.

Examples

In the following example we retrieve the list of classes set on a <span> element as a DOMTokenList using Element.classList. We then test for the existence of "c" in the list, and write the result into the <span>'s Node.textContent.

First, the HTML:

html
<span class="a b c"></span>

Now the JavaScript:

js
const span = document.querySelector("span");
span.textContent = span.classList.contains("c")
  ? "The classList contains 'c'"
  : "The classList does not contain 'c'";

The output looks like this:

Specifications

Specification
DOM Standard
# ref-for-dom-domtokenlist-contains①

Browser compatibility

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