DOMTokenList: add() 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 add() method of the DOMTokenList interface adds the given tokens to the list, omitting any that are already present.

Syntax

js
add(token1)
add(token1, token2)
add(token1, token2, /* …, */ tokenN)

Parameters

tokenN

A string representing a token (or tokens) to add to the DOMTokenList.

Return value

None.

Exceptions

SyntaxError DOMException

Thrown if one of the arguments is an empty string

InvalidCharacterError DOMException

Thrown if a token contains ASCII whitespace.

Examples

In the following example, we retrieve the list of classes set on a <span> element as a DOMTokenList, using Element.classList. We then add a new token to the list, and write the list 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");
const classes = span.classList;
classes.add("d");
span.textContent = classes;

The output looks like this:

You can add multiple tokens as well:

js
span.classList.add("d", "e", "f");

Specifications

Specification
DOM Standard
# ref-for-dom-domtokenlist-add①

Browser compatibility

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