code: function(id){
  		var rtv = null;
  		_visitNode(this.documentElement,function(node){
  			if(node.nodeType == ELEMENT_NODE){
  				if(node.getAttribute('id') == id){
  					rtv = node;
  					return true;
  				}
  			}
  		})
  		return rtv;
  	}
docs: Introduced in DOM Level 2: