--- /dev/null
+<?php
+error_reporting(0);
+
+$ts = $_REQUEST['ts'];
+$etag = md5($ts);
+
+$ifNoneMatch = isset($_SERVER['HTTP_IF_NONE_MATCH']) ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) : false;
+if ($ifNoneMatch == $etag) {
+ header('HTTP/1.0 304 Not Modified');
+ die; // stop processing
+}
+
+header("Etag: " . $etag);
+echo "OK: " . $etag;
+
+?>