Node.isDefaultNamespace()

The isDefaultNamespace() method of the Node interface accepts a namespace URI as an argument. It returns a boolean value that is true if the namespace is the default namespace on the given node and false if not.

Note: The default namespace of an HTML element is always "". For a SVG element, it is set by the xmlns attribute.

Syntax

isDefaultNamespace(namespaceURI);

Parameters

namespaceURI

A string representing the namespace against which the element will be checked.

Note: namespaceURI is not an optional parameter, but can be null.

Return value

A boolean value that holds the return value true or false, indicating if the parameter is the default namespace, or not.

Example

Is "" the default namespace for &lt;output&gt;: <output>Not tested</output>.<br/>
Is "http://www.w3.org/2000/svg" the default namespace for &lt;output&gt;: <output>Not tested</output>.<br/>
Is "" the default namespace for &lt;svg&gt;: <output>Not tested</output>.<br/>
Is "http://www.w3.org/2000/svg" the default namespace for &lt;svg&gt;: <output>Not tested</output>.<br/>
<svg xmlns="http://www.w3.org/2000/svg" height="1"></svg>
<button>Click to see the results</button>

const button = document.getElementsByTagName('button')[0];
button.addEventListener("click", function () {
  const aHtmlElt = document.getElementsByTagName('output')[0];
  const aSvgElt = document.getElementsByTagName('svg')[0];

  const result = document.getElementsByTagName('output');
  result[0].value = aHtmlElt.isDefaultNamespace(""); // true
  result[1].value = aHtmlElt.isDefaultNamespace("http://www.w3.org/2000/svg"); // false
  result[2].value = aSvgElt.isDefaultNamespace(""); // true
  result[3].value = aSvgElt.isDefaultNamespace("http://www.w3.org/2000/svg"); // false
});

Specifications

Specification
DOM Standard
# dom-node-isdefaultnamespace

Browser compatibility

BCD tables only load in the browser

See also