$contents = htmlentities(file_get_contents($url));

$dom = new DOMDocument;
$dom->loadHTML($contents);

$xpath = new DOMXpath($dom);
$data = $xpath->query('//input[@id="__VIEWSTATE"]');
var_dump($data);


I GEt:
object(DOMNodeList)#3 (1) { ["length"]=> int(0) }