Element.prefix
Element.prefix 只读属性返回指定元素的命名空间前缀，如果未指定前缀，则返回 null。
备注： 在 DOM4 之前，该 API 是在 Node interface 中定义的。
Syntax
string = element.prefix
Examples
The following logs "x" to the console.
<x:div onclick="console.log(this.prefix)"/>
Notes
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.
Specifications
| Specification |
|---|
| DOM Standard # ref-for-dom-element-prefix① |
Browser compatibility
BCD tables only load in the browser