CSSRule - Web API 接口参考 编辑

CSSRule 接口表示一条 CSS 规则。有几种不同的规则类型，在下面的类型常量部分中有悉数列出。

CSSRule 接口指定了所有类型的规则的公共属性，而特定类型的规则的专有属性则在这些规则各自类型的、更专用的接口中被指定。

可以通过 CSSStyleSheet 的 cssRules 列表了解更多关于 CSSRule 的介绍。

所有 CSSRule 实例共有的属性

CSSRule.cssText

返回规则的文本表示. 例如 "h1,h2 { font-size: 16pt }"

CSSRule.parentRule 只读

返回包含规则，否则返回 null。例如：如果此规则是 @media 块中的样式规则, 则其父规则将是该 CSSMediaRule。

CSSRule.parentStyleSheet 只读

返回包含此规则的样式表的 CSSStyleSheet 对象。

CSSRule.type 只读

规则类型，表示 CSS 规则类型 类型常量 中的一种类型。

常量

类型常量

CSSRule接口通过一系列整型常量来约束CSSRule的type取值范围，同时这些常量也对应规则的具体实现接口。这些常量和接口的对应关系如下：

类型	值	对应接口	备注与示例
CSSRule.STYLE_RULE	1	CSSStyleRule	最常见的一种规则。 selector { prop1: val1; prop2: val2; }
CSSRule.IMPORT_RULE	3	CSSImportRule	一条 @import 规则。(Until the documentation is completed, see the interface definition in the Mozilla source code: nsIDOMCSSImportRule.)
CSSRule.MEDIA_RULE	4	CSSMediaRule
CSSRule.FONT_FACE_RULE	5	CSSFontFaceRule
CSSRule.PAGE_RULE	6	CSSPageRule
CSSRule.KEYFRAMES_RULE	7	CSSKeyframesRule
CSSRule.KEYFRAME_RULE	8	CSSKeyframeRule
Reserved for future use	9		应当会在将来被用于定义颜色配置
CSSRule.NAMESPACE_RULE	10	CSSNamespaceRule
CSSRule.COUNTER_STYLE_RULE	11	CSSCounterStyleRule
CSSRule.SUPPORTS_RULE	12	CSSSupportsRule
CSSRule.DOCUMENT_RULE	13	CSSDocumentRule
CSSRule.FONT_FEATURE_VALUES_RULE	14	CSSFontFeatureValuesRule
CSSRule.VIEWPORT_RULE	15	CSSViewportRule
CSSRule.REGION_STYLE_RULE	16	CSSRegionStyleRule
CSSRule.UNKNOWN_RULE	0	CSSUnknownRule
CSSRule.CHARSET_RULE	2	CSSCharsetRule	（已在大多数浏览器中被移除）

An up-to-date informal list of constants can be found on the CSSWG Wiki.

语法

使用 WebIDL 语法格式进行描述。

interface CSSRule {
    const unsigned short STYLE_RULE = 1;
    const unsigned short CHARSET_RULE = 2;
    const unsigned short IMPORT_RULE = 3;
    const unsigned short MEDIA_RULE = 4;
    const unsigned short FONT_FACE_RULE = 5;
    const unsigned short PAGE_RULE = 6;
    const unsigned short KEYFRAMES_RULE = 7;
    const unsigned short KEYFRAME_RULE = 8;
    const unsigned short NAMESPACE_RULE = 10;
    const unsigned short COUNTER_STYLE_RULE = 11;
    const unsigned short SUPPORTS_RULE = 12;
    const unsigned short DOCUMENT_RULE = 13;
    const unsigned short FONT_FEATURE_VALUES_RULE = 14;
    const unsigned short VIEWPORT_RULE = 15;
    const unsigned short REGION_STYLE_RULE = 16;
    readonly attribute unsigned short type;
    attribute DOMString cssText;
    readonly attribute CSSRule? parentRule;
    readonly attribute CSSStyleSheet? parentStyleSheet;
};

规范

规范	状态	备注
CSS Object Model (CSSOM) CSSRule	Working Draft	Obsoleted values CHARSET_RULE and UNKNOWN_RULE. Added value NAMESPACE_RULE.
CSS Animations CSSRule	Working Draft	Added values KEYFRAMES_RULE and KEYFRAME_RULE.
CSS Fonts Module Level 4 CSSRule	Working Draft	Added value FONT_FEATURE_VALUES_RULE.
CSS Counter Styles Level 3 CSSRule	Candidate Recommendation	Added value COUNTER_STYLE_RULE.
CSS Conditional Rules Module Level 3 CSSRule	Candidate Recommendation	Added value SUPPORTS_RULE. (DOCUMENT_RULE has been pushed to CSS Conditional Rules Level 4)
Document Object Model (DOM) Level 2 Style Specification CSSRule	Obsolete	Initial definition.

浏览器兼容性

BCD tables only load in the browser

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.

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