DOMTokenList: add() method

{{APIRef("DOM")}}

The add() method of the {{domxref("DOMTokenList")}} interface adds the given tokens to the list, omitting any that are already present.

Syntax

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 {{domxref("DOMException")}}
  • : Thrown if one of the arguments is an empty string
• InvalidCharacterError {{domxref("DOMException")}}
  • : Thrown if a token contains ASCII whitespace.

Examples

In the following example, we retrieve the list of classes set on a {{htmlelement("span")}} element as a DOMTokenList, using {{domxref("Element.classList")}}. We then add a new token to the list, and write the list into the <span>'s {{domxref("Node.textContent")}}.

First, the HTML:

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

Now the JavaScript:

const span = document.querySelector("span");
const classes = span.classList;
classes.add("d");
span.textContent = classes;

The output looks like this:

{{ EmbedLiveSample('Examples', '100%', 60) }}

You can add multiple tokens as well:

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}