void deleteRule(unsigned long index) throws DOMException;
index
The index within the cssRules array of the rule to be deleted.
This method throws a DOMException with a code of INDEX_SIZE_ERR if index is negative or greater than or equal to cssRules.length. It throws a DOMException with a code of NO_MODIFICATION_ALLOWED_ERR if this style sheet is read-only.
This method deletes the rule at the specified index from the cssRules array.