The Node.lookupNamespaceURI() method accepts a prefix and returns the namespace URI associated with it on the given node if found (and null if not).


var namespace = node.lookupNamespaceURI(prefix);


The prefix to look for. If this parameter is null, the method will return the default namespace URI, if any.

Return value

A DOMString containing the the namespace URI. If the prefix is not found, it returns null.


Specification Status Comment
The definition of 'Node: lookupNamespaceURI' in that specification.
Living Standard

Browser compatibility

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ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
lookupNamespaceURIChrome Full support YesEdge Full support 12Firefox Full support YesIE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes


Full support  
Full support
Compatibility unknown  
Compatibility unknown

In Firefox, due to bug 312019, this method does not work with dynamically assigned namespaces (i.e., those set with Node.prefix).