为页面浏览刮刮Facebook页面

I wrote a simple script for scraping Facebook to get the page likes using Advanced HTML Dom.

require_once('../advanced_html_dom.php');

$html = file_get_html("https://www.facebook.com/powerschool"); // you don't need to use curl
$followers = $html->find('._4bl9', 0)->plaintext;

echo "page likes: " . $followers;

Although I believe I've targeted the correct class to get the value, the value for followers comes up blank.

Does the page load via AJAX or something and I need to use something like PhantomJS or am I doing this wrong? Thanks !