@namespace
is an at-rule that defines XML namespaces to be used in a CSS style sheet. The defined namespaces can be used to restrict the universal, type, and 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.
The @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.
In HTML5, known foreign elements will be 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
).
Note: 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.
/* Default namespace */ @namespace url(XML-namespace-URL); @namespace "XML-namespace-URL"; /* Prefixed namespace */ @namespace prefix url(XML-namespace-URL); @namespace prefix "XML-namespace-URL";
@namespace <namespace-prefix>? [ <string> | <uri> ];where
<namespace-prefix> = <ident>
@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 {}
Specification | Status | Comment |
---|---|---|
CSS Namespaces Module The definition of '@namespace' in that specification. | Recommendation | Initial definition |
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 1.0 | 1.0 (1.7 or earlier) | 9.0 | 8.0 | 1.0 |
Namespace selector (|) | 1.0 | 1.0 (1.7 or earlier) | 9.0 | 8.0 | 3.0 |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | ? | ? | ? | ? | ? | ? |
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/@namespace