row->GetParentNode(getter_AddRefs(parent));
nsCOMPtr<nsIDOMNode> parent;
nsHTMLTableElement::DeleteRow(PRInt32 aValue){  nsCOMPtr<nsIDOMHTMLCollection> rows;  GetRows(getter_AddRefs(rows));  nsCOMPtr<nsIDOMNode> row;  rows->Item(aValue, getter_AddRefs(row));  if (row) {    nsCOMPtr<nsIDOMNode> parent=nsnull;    row->GetParentNode(getter_AddRefs(parent));    if (parent) {      nsCOMPtr<nsIDOMNode> deleted_row;      parent->RemoveChild(row, getter_AddRefs(deleted_row));    }  }  return NS_OK;}