Node: isDefaultNamespace() 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 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

js
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

html
Is "" the default namespace for <output>:
<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 run tests</button>
js
const button = document.querySelector("button");
button.addEventListener("click", () => {
  const aHtmlElt = document.querySelector("output");
  const aSvgElt = document.querySelector("svg");

  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(""); // false
  result[3].value = aSvgElt.isDefaultNamespace("http://www.w3.org/2000/svg"); // true
});

Specifications

Specification
DOM
# dom-node-isdefaultnamespace

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
isDefaultNamespace

Legend

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Full support
Full support

See also