Element: setAttributeNodeNS() 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 setAttributeNodeNS() method of the Element interface adds a new namespaced Attr node to an element.

If you don't need to work with the attribute node (such as cloning from another element) before adding it, you can use the setAttributeNS() method instead.

If you are working with HTML documents and you don't need to specify the requested attribute as being part of a specific namespace, use the setAttribute() method instead.

Syntax

js
setAttributeNodeNS(attributeNode)

Parameters

attributeNode

The Attr node to add to the element.

Return value

The replaced attribute node, if any, returned by this function.

Examples

js
// <div id="one" xmlns:myNS="http://www.mozilla.org/ns/specialspace"
//            myNS:special-align="utterleft">one</div>
// <div id="two">two</div>

const myns = "http://www.mozilla.org/ns/specialspace";
const d1 = document.getElementById("one");
const d2 = document.getElementById("two");
const a = d1.getAttributeNodeNS(myns, "special-align");
d2.setAttributeNodeNS(a.cloneNode(true));
alert(d2.attributes[1].value); // returns: `utterleft'

Notes

If the specified attribute already exists on the element, then that attribute is replaced with the new one and the replaced one is returned.

Note that if you try to set without cloning the node, you may see NS_ERROR_DOM_INUSE_ATTRIBUTE_ERR "Attribute already in use" error, as the DOM requires cloning for Attr to be reused (unlike other Nodes which can be moved).

Specifications

Specification
DOM
# dom-element-setattributenodens

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
setAttributeNodeNS
Chrome – Full support
Chrome 1 (Release date: 2008-12-11)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote
footnote Returns a ClientRectList with ClientRect objects (which do not contain x and y properties) instead of DOMRect objects.
Firefox – Full support
Firefox 1 (Release date: 2004-11-09)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 1 (Release date: 2003-06-23)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 4 (Release date: 2011-03-29)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 1 (Release date: 2007-06-29)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 1 (Release date: 2007-06-29)
footnote Full support
Emoji and more Unicode in element and attribute names and namespace prefix (valid names match HTML parser)
Chrome – Full support
Chrome 143 (Release date: 2025-12-02)
footnote Full support
Edge – Full support
Edge 143 (Release date: 2025-12-05)
footnote Full support
Firefox – Full support
Firefox 149 (Release date: 2026-03-24)
footnote Full support
Opera – Full support
Opera 127 (Release date: 2026-02-02)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – Full support
Chrome Android 143 (Release date: 2025-12-02)
footnote Full support
Firefox for Android – Full support
Firefox for Android 149 (Release date: 2026-03-24)
footnote Full support
Opera Android – Full support
Opera Android 94 (Release date: 2026-01-13)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – Full support
WebView Android 143 (Release date: 2025-12-02)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
See implementation notes.

See also