public function openHref($href, $pageUrl = NULL)
 {
     $bak = XPathHelper::$_curlopts;
     XPathHelper::$_curlopts[CURLOPT_USERAGENT] = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.97 Safari/537.11";
     $res = parent::openHref($href);
     XPathHelper::$_curlopts = $bak;
     return $res;
 }