This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The Element.prefix read-only property returns the namespace prefix of the specified element, or null if no prefix is specified.
A string.
The following logs "x" to the console.
<x:div onclick="console.log(this.prefix)"/>
This will only work when a namespace-aware parser is used, i.e., when a document is served with an XML MIME type. This will not work for HTML documents.
| Specification |
|---|
| DOM> # ref-for-dom-element-prefix①> |
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | |
prefix |
1 | 12 | 1 | ≤12.1 | 1 | 18 | 4 | ≤12.1 | 1 | 1.0 | 4.4 | 1 |
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https://developer.mozilla.org/en-US/docs/Web/API/Element/prefix