We're looking for a user researcher to understand the needs of developers and designers. Is this you or someone you know? Check out the post: https://mzl.la/2IGzdXS

DOMTokenList.keys()

The keys() method of the DOMTokenList interface returns an iterator allowing to go through all keys contained in this object. The keys are of type unsigned integer.

Syntax

tokenList.keys();

Parameters

None.

Return value

Returns an iterator.

Examples

In the following example we retrieve the list of classes set on a <span> element as a DOMTokenList using Element.classList. We when retrieve an iterator containing the keys using values(), then iterate through those keys using a for ... of loop, writing each one to the <span>'s Node.textContent.

First, the HTML:

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

Now the JavaScript:

var span = document.querySelector("span");
var classes = span.classList;
var iterator = classes.keys();

for(var value of iterator) {
  span.textContent += value + ' ++ ';
}

The output looks like this:

Specifications

Specification Status Comment
DOM
The definition of 'keys() (as iterable<Node>)' in that specification.
Living Standard Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes ?50 ? Yes ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes ?50 Yes ? Yes

Document Tags and Contributors

Contributors to this page: fscholz, chrisdavidmills, teoli
Last updated by: fscholz,