Element.namespaceURI
 The Element.namespaceURI read-only property returns the namespace URI of the element, or null if the element is not in a namespace. 
Value
A string, or null.
Examples

 In this snippet, an element is being examined for its localName and its namespaceURI. If the namespaceURI returns the XUL namespace and the localName returns "browser", then the node is understood to be a XUL <browser/>.  if (element.localName == "browser" &&
    element.namespaceURI == "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul") {
  // this is a XUL browser
}


Notes

 This is not a computed value that is the result of a namespace lookup based on an examination of the namespace declarations in scope. The namespace URI of a node is frozen at the node creation time.   In Firefox 3.5 and earlier, the namespace URI for HTML elements in HTML documents is null. In later versions, in compliance with HTML5, it is http://www.w3.org/1999/xhtml as in XHTML.   You can create an element with the specified namespaceURI using the DOM Level 2 method document.createElementNS.   The DOM does not handle or enforce namespace validation per se. It is up to the DOM application to do any validation necessary. Also note that the namespace prefix, once it is associated with a particular element, cannot be changed. 

Specifications

Specification
DOM Standard # ref-for-dom-element-namespaceuri①

Browser compatibility




Desktop
Mobile



Chrome
Edge
Firefox
Internet Explorer
Opera
Safari
WebView Android
Chrome Android
Firefox for Android
Opera Android
Safari on IOS
Samsung Internet



namespaceURI
1
12
1
9
≤12.1
1
1
18
4
≤12.1
1
1.0


See also
 Element.localName Element.prefix Attr.namespaceURI 


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Last modified: Mar 29, 2022, by MDN contributors


    
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