CSSNamespaceRule: namespaceURI property

The read-only namespaceURI property of the CSSNamespaceRule returns a string containing the text of the URI of the given namespace.

Value

A string containing a URI.

Examples

The stylesheet includes a namespace as the only rule. Therefore the first CSSRule returned will be a CSSNamespaceRule. The value of the namespaceURI property will be http://www.w3.org/1999/xhtml.

css
@namespace url("http://www.w3.org/1999/xhtml");
js
const myRules = document.styleSheets[0].cssRules;
console.log(myRules[0].namespaceURI); // 'http://www.w3.org/1999/xhtml'

Specifications