CSSRule

The CSSRule interface represents a single CSS rule. There are several types of rules, listed in the Type constants section below.

The CSSRule interface specifies the properties common to all rules, while properties unique to specific rule types are specified in the more specialized interfaces for those rules' respective types.

References to a CSSRule may be obtained by looking at a CSSStyleSheet's cssRules list.

Properties common to all CSSRule instances

CSSRule.cssText
Represents the textual representation of the rule, e.g. "h1,h2 { font-size: 16pt }" or "@import 'url'". To access or modify parts of the rule (e.g. the value of "font-size" in the example) use the properties on the specialized interface for the rule's type.
CSSRule.parentRule Read only
Returns the containing rule, otherwise null. E.g. if this rule is a style rule inside an @media block, the parent rule would be that CSSMediaRule.
CSSRule.parentStyleSheet Read only
Returns the CSSStyleSheet object for the style sheet that contains this rule
CSSRule.type Read only
One of the Type constants indicating the type of CSS rule.

Constants

Type constants

The CSSRule interface specifies integer constants that can be used in conjunction with a CSSRule's type property to discern the rule type (and therefore, which specialized interface it implements). The relationships between these constants and the interfaces are:

Type Value Rule-specific interface Comments and examples
CSSRule.STYLE_RULE 1 CSSStyleRule The most common kind of rule:
selector { prop1: val1; prop2: val2; }
CSSRule.IMPORT_RULE 3 CSSImportRule An @import rule. (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 Should be used to define color profiles in the future
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 (Removed in most browsers.)

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

Specifications

Specification Status Comment
CSS Object Model (CSSOM)
The definition of 'CSSRule' in that specification.
Working Draft Obsoleted values CHARSET_RULE and UNKNOWN_RULE. Added value NAMESPACE_RULE.
CSS Animations
The definition of 'CSSRule' in that specification.
Working Draft Added values KEYFRAMES_RULE and KEYFRAME_RULE.
CSS Fonts Module Level 4
The definition of 'CSSRule' in that specification.
Working Draft Added value FONT_FEATURE_VALUES_RULE.
CSS Counter Styles Level 3
The definition of 'CSSRule' in that specification.
Candidate Recommendation Added value COUNTER_STYLE_RULE.
CSS Conditional Rules Module Level 3
The definition of 'CSSRule' in that specification.
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
The definition of 'CSSRule' in that specification.
Obsolete Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
CSSRuleChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 9Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0
cssTextChrome Full support 1Edge Full support 12Firefox Full support 1IE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0
parentRuleChrome Full support 1Edge Full support 12Firefox Full support 1IE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0
parentStyleSheetChrome Full support 1Edge Full support 12Firefox Full support 1IE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0
typeChrome Full support 1Edge Full support 12Firefox Full support 1IE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0

Legend

Full support
Full support
Compatibility unknown
Compatibility unknown

See also