The forEach()
method of the DOMTokenList
interface calls the callback given in parameter once for each value pair in the list, in insertion order.
Syntax
tokenList.forEach(callback [, thisArg]);
Parameters
callback
- Function to execute for each element, eventually taking three arguments:
currentValue
- The current element being processed in the array.
currentIndex
- The index of the current element being processed in the array.
listObj
- The array that
forEach()
is being applied to.
thisArg
Optional- Value to use as
this
when executingcallback
.
Return value
Example
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 values using forEach()
, writing each one to the <span>
's Node.textContent
inside the forEach()
inner function.
HTML
<span class="a b c"></span>
JavaScript
let span = document.querySelector("span"); let classes = span.classList; let iterator = classes.values(); classes.forEach( function(value, key, listObj) { span.textContent += `${value} ${key}/${this} ++ `; }, "arg" );
Result
Polyfill
This polyfill adds compatibility to all Browsers supporting ES5:
if (window.DOMTokenList && !DOMTokenList.prototype.forEach) { DOMTokenList.prototype.forEach = function (callback, thisArg) { thisArg = thisArg || window; for (var i = 0; i < this.length; i++) { callback.call(thisArg, this[i], i, this); } }; }
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'forEach() (as iterable<Node>)' 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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
forEach | Chrome Full support 45 | Edge Full support 16 | Firefox Full support 50 | IE No support No | Opera Full support 32 | Safari Full support 10 | WebView Android Full support 45 | Chrome Android Full support 45 | Firefox Android Full support 50 | Opera Android Full support 32 | Safari iOS Full support 10 | Samsung Internet Android Full support 5.0 |
Legend
- Full support
- Full support
- No support
- No support
See also
DOMSettableTokenList
(object that extends DOMTokenList with settable .value property)