setAttributeNodeNS adds a new namespaced attribute node to an element.




  • attributeNode is an Attr node.

Return value

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


// <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");
alert(d2.attributes[1].value); // returns: `utterleft'


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, Mozilla gives an 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).

DOM methods dealing with element's attributes:

Not namespace-aware, most commonly used methods Namespace-aware variants (DOM Level 2) DOM Level 1 methods for dealing with Attr nodes directly (seldom used) DOM Level 2 namespace-aware methods for dealing with Attr nodes directly (seldom used)
setAttribute (DOM 1) setAttributeNS setAttributeNode setAttributeNodeNS
getAttribute (DOM 1) getAttributeNS getAttributeNode getAttributeNodeNS
hasAttribute (DOM 2) hasAttributeNS - -
removeAttribute (DOM 1) removeAttributeNS removeAttributeNode -


DOM Standard
# dom-element-setattributenodens

Browser compatibility

BCD tables only load in the browser

See also