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• 句法
• 描述
• 形式句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

@namespace 是 at-rule that defines XML namespaces to be used in a CSS style sheet .

句法

/* Default namespace */
@namespace url(XML-namespace-URL);
@namespace "XML-namespace-URL";
/* Prefixed namespace */
@namespace prefix url(XML-namespace-URL);
@namespace prefix "XML-namespace-URL";
					

描述

The defined namespaces can be used to restrict the universal , type ，和 attribute selectors to only select elements within that namespace. The @namespace rule is generally only useful when dealing with documents containing multiple namespaces—such as HTML5 with inline SVG or MathML, or XML that mixes multiple vocabularies.

Any @namespace rules must follow all @charset and @import rules, and precede all other at-rules and style declarations in a style sheet.

@namespace can be used to define the default namespace for the style sheet. When a default namespace is defined, all universal and type selectors (but not attribute selectors, see note below) apply only to elements in that namespace.

@namespace rule can also be used to define a namespace prefix . When a universal, type, or attribute selector is prefixed with a namespace prefix, then that selector only matches if the namespace and name of the element or attribute matches.

在 HTML5 , known foreign elements will automatically be assigned namespaces. This means that HTML elements will act as though they are in the XHTML namespace ( http://www.w3.org/1999/xhtml ), even if there is no xmlns attribute anywhere in the document, and the <svg> and <math> elements will be assigned their proper namespaces ( http://www.w3.org/2000/svg and http://www.w3.org/1998/Math/MathML ).

注意： In XML, unless a prefix is defined directly on an attribute ( e.g. , xlink:href ), that attribute has no namespace. In other words, attributes do not inherit the namespace of the element they're on. To match this behaviour, the default namespace in CSS does not apply to attribute selectors.

形式句法

@namespace <namespace-prefix>? [ <string> | <url> ];
where 
<namespace-prefix> = <ident>
					

范例

Specifying default and prefixed namespaces

@namespace url(http://www.w3.org/1999/xhtml);
@namespace svg url(http://www.w3.org/2000/svg);
/* This matches all XHTML <a> elements, as XHTML is the default unprefixed namespace */
a {}
/* This matches all SVG <a> elements */
svg|a {}
/* This matches both XHTML and SVG <a> elements */
*|a {}
					

规范

规范	状态	注释
CSS Namespaces Module The definition of '@namespace' in that specification.	推荐	初始定义

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
@namespace	Chrome 完整支持 1	Edge 完整支持 12	Firefox 完整支持 1	IE 完整支持 9	Opera 完整支持 8	Safari 完整支持 1	WebView Android 完整支持 37	Chrome Android 完整支持 18	Firefox Android 完整支持 4	Opera Android 完整支持 14	Safari iOS 完整支持 1	Samsung Internet Android 完整支持 1.0

图例

完整支持

完整支持

另请参阅

• Namespaces crash course

元数据

• 最后修改： Jul 22, 2020

相关话题

1. CSS
2. CSS 参考
3. CSS Namespaces
4. At-Rules

   1. @namespace