public function getDOMDocument()
    {
        $node = $this->getNode(0);
        $r = null;
        if ($node instanceof \DOMElement
            && $node->ownerDocument instanceof \DOMDocument
        ) {
            $r = $node->ownerDocument;
        }
        return $r;
    }
public function getDOMDocument()
    {
        $node = $this->getNode(0);
        $r = null;
        if ($node instanceof \DOMElement
            && $node->ownerDocument instanceof \DOMDocument
        ) {
            $r = $node->ownerDocument;
        }
        return $r;
    }
public function getDOMDocument ( ) { $ node = $ this -> getNode ( 0 ) ; $ r = null ; if ( $ node instanceof \ DOMElement && $ node -> ownerDocument instanceof \ DOMDocument ) { $ r = $ node -> ownerDocument ; } return $ r ; }
get ownerDocument of the first element

@return \DOMDocument|null
get ownerDocument of the first element