* @param node the node to convert.
* @return the node as a header element.
* @exception XPCOMException if the node is not a heading.
*/
public static nsIDOMHTMLHeadingElement asHeading(nsIDOMNode node) {
nsIDOMHTMLHeadingElement heading = (nsIDOMHTMLHeadingElement) node.queryInterface(nsIDOMHTMLHeadingElement.NS_IDOMHTMLHEADINGELEMENT_IID);
return heading;
}