<?php error_reporting(0); $ts = $_REQUEST['ts']; $ifModifiedSince = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']) : false; if ($ifModifiedSince == $ts) { header('HTTP/1.0 304 Not Modified'); die; // stop processing } header("Last-Modified: " . $ts); if ( $ifModifiedSince ) { echo "OK: " . $ts; } else { echo "FAIL"; } ?>