ดึงข้อมูล xml แต่ไฟล์เวปเป็น .php ดึงแบบ xml ไม่ได้

<?php

$dom = new DOMDocument("1.0","UTF-8");
$dom1 = new DOMDocument("1.0","UTF-8");
$dom->load("test.com/test2.php");
$data1 = $dom->getElementsByTagName("school");

$data2 = $dom->getElementsByTagName("student");
foreach($data2 as $Price)
{	
	if($Price->attributes->item(0)->textContent == 'bob'){
		$data3 = $Price->getElementsByTagName("name");
		foreach($data3 as $Ask)
		{                   
				                 echo "ชื่อ" . $Ask->textContent."<br>";	
		}
	}
}

?>