The CSSRule interface is the abstract base interface for any type of CSS statement. This includes both rule sets and at-rules. An implementation is expected to preserve all rules specified in a CSS style sheet, even if the rule is not recognized by the parser. Unrecognized rules are represented using the CSSUnknownRule interface.

An integer indicating which type of rule this is.

The rule is a CSSUnknownRule.

The rule is a CSSStyleRule.

The rule is a CSSCharsetRule.

The rule is a CSSImportRule.

The rule is a CSSMediaRule.

The rule is a CSSFontFaceRule.

The rule is a CSSPageRule.

The type of the rule, as defined above. The expectation is that binding-specific casting methods can be used to cast down from an instance of the CSSRule interface to the specific derived interface implied by the type.

The parsable textual representation of the rule. This reflects the current state of the rule and not its initial value.

SYNTAX_ERR: Raised if the specified CSS string value has a syntax error and is unparsable.

INVALID_MODIFICATION_ERR: Raised if the specified CSS string value represents a different type of rule than the current one.

HIERARCHY_REQUEST_ERR: Raised if the rule cannot be inserted at this point in the style sheet.

NO_MODIFICATION_ALLOWED_ERR: Raised if the rule is readonly.

The style sheet that contains this rule.

If this rule is contained inside another rule (e.g. a style rule inside an @media block), this is the containing rule. If this rule is not nested inside any other rules, this returns null.