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/DOM

element.className

className gets and sets the value of the class attribute of the specified element.

Syntax

var cName = elementNodeReference.className;
elementNodeReference.className = cName;
  • cName is a string variable representing the class or space-separated classes of the current element.

Example

let elm = document.getElementById('item');

if(elm.className === 'active'){
    elm.className = 'inactive';
} else {
    elm.className = 'active';
}

Notes

The name className is used for this property instead of class because of conflicts with the "class" keyword in many languages which are used to manipulate the DOM.

className can also be an instance of SVGAnimatedString if the element is an SVGElement. It is better to get/set the className of an element using Element.getAttribute and Element.setAttribute if you are dealing with SVG elements

elm.setAttribute('class', elm.getAttribute('class'))

Specifications

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android webview Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/element/className