CSS Object Model - CSSGroupingRule

The CSSGroupingRule interface represents an at-rule that contains other rules nested inside itself.

Properties
CSSRuleList	cssRules The cssRules attribute must return a CSSRuleList object for the child CSS rules.

Operations
void	deleteRule(unsigned long index) The deleteRule(index) method must remove a CSS rule from the child CSS rules at index.
unsigned long	insertRule(DOMString rule, unsigned long index) The insertRule(rule, index) method must return the result of invoking insert a CSS rule rule into the child CSS rules at index.