Web/API/DOMTokenList/contains

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

Syntax

tokenList.contains(token);

Parameters

token

A DOMString representing the token you want to check for the existance of in the list.

Return value

A Boolean, 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:

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

Now the JavaScript:

let span = document.querySelector("span");
let classes = span.classList;
let result = classes.contains("c");
if (result) {
  span.textContent = "The classList contains 'c'";
} else {
   span.textContent = "The classList does not contain 'c'";
}

The output looks like this:

Specifications

Specification	Status	Comment
DOMThe definition of 'contains()' in that specification.	Living Standard	Initial definition

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
contains	Chrome Full support 8	Edge Full support 12	Firefox Full support Yes	IE Full support 10	Opera Full support Yes	Safari Full support 5.1	WebView Android Full support 3	Chrome Android Full support 18	Firefox Android Full support Yes	Opera Android Full support Yes	Safari iOS Full support 5.1	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

DOMTokenList.contains() by Mozilla Contributors is licensed under CC-BY-SA 2.5.