This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2018.
The read-only namespaceURI property of the CSSNamespaceRule returns a string containing the text of the URI of the given namespace.
A string containing a URI.
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.
@namespace url("http://www.w3.org/1999/xhtml");
const myRules = document.styleSheets[0].cssRules; console.log(myRules[0].namespaceURI); // 'http://www.w3.org/1999/xhtml'
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | |
namespaceURI |
47 | 12 | 59 | 36 | 10.1 | 47 | 59 | 36 | 10.3 | 5.0 | 47 | 10.3 |
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https://developer.mozilla.org/en-US/docs/Web/API/CSSNamespaceRule/namespaceURI