使用simplehtmldom进行刮擦会给我空洞的结果

I am trying to scrape a website using simplehtmldom but it is giving me an empty result.

Here is my code:

<?php
    include('../simple_html_dom.php');
    ini_set("user_agent","Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0");


 echo $html = file_get_html('https://www.bodybuilding.com/store/opt/whey.html');
?>