if (nsnull!=aValue) {
if (aValue) {
nsHTMLTableElement::SetCaption(nsIDOMHTMLTableCaptionElement* aValue){  nsresult rv = DeleteCaption();  if (NS_SUCCEEDED(rv)) {    if (nsnull!=aValue) {      nsCOMPtr<nsIDOMNode> resultingChild;      AppendChild(aValue, getter_AddRefs(resultingChild));    }  }  return rv;}