file_get_contents获取酷狗网页时，<audio>标签的src为空

Question

 $urlBefore = "https://www.kugou.com/song/#";
   foreach ($urlData as $key => $value) {
    $url = $urlBefore . "hash=" . $value["hash"] ."&album_id=".$value['album_id'];
    echo $url."<br/>";
   $htmlFile =phpQuery::newDocumentFileHTML($url);
   $title = pq("#myAudio");
   $url0 = pq($title[0])->attr("src");
   print($url0."<br/>");

}

//$url0变量为空，网站源码可以获取，但是<audio>标签的src属性的值为unknown,这是被屏蔽了吗，我要如何获取？