private static function _getNodePath($node)
    {
        $ret = array();
        $doc = $node->ownerDocument;
        $parentNode = $node->parentNode;

        while ($parentNode !== null && !$doc->isSameNode($parentNode)) {
            // gets the sibling position
            $pos = 0;
            foreach ($parentNode->childNodes as $i => $childNode) {
                if ($childNode->isSameNode($node)) {
                    $pos = $i;
                    break;
                }
            }

            array_unshift($ret, $pos);
            $node = $parentNode;
            $parentNode = $node->parentNode;
        }

        return $ret;
    }