note 33484 added to function.ob-end-clean

You might want to prevent your script from executing if the client already has the latest version. You can do it like so: ob_start(); $mtime=filemtime($_SERVER["SCRIPT_FILENAME"])-date("Z"); $gmt_mtime = date('D, d M Y H:i:s', $mtime) . ' GMT'; $headers = getallheaders(); if(isset($headers["If-Modified-Since"])) { if ($headers["If-Modified-Since"] == $gmt_mtime) { header("HTTP/1.1 304 Not Modified"); ob_end_clean(); exit; } } $size=ob_get_length(); header("Last-Modified: ".$gmt_mtime); header("Content-Length: $size"); ob_end_flush(); Instead of checking the If-Modified-Since-Header against the date of the last modification of the script, you can of course query a database or take any other date that is somehow related to the modification of the result of your script. You can for instance use this technique to generate images dynamically. If the user indicates he already has a version of the image by the If-Modified-Since-Header, there's no need to generate it and let the server finally discard it because the server only then interpretes the If-Modified-Since-Header. This saves server load and shortens response-times. ---- Manual Page -- http://www.php.net/manual/en/function.ob-end-clean.php Edit Note -- http://master.php.net/manage/user-notes.php?action=edit+33484 Delete Note -- http://master.php.net/manage/user-notes.php?action=delete+33484&report=yes Reject Note -- http://master.php.net/manage/user-notes.php?action=reject+33484&report=yes