log out help

I have a log in script that set's a cookie, each page they visit looks for this cookie, if they don't have it, they are directed to the log in screen. When user's log out it runs the script below to delete the cookie, which works fine.

<?php 
$past = time() - 200; 
//this makes the time in the past to destroy the cookie 
setcookie(ID_my_site, gone, $past); 
setcookie(Key_my_site, gone, $past); 
header("Location: /gaming/index2.php"); 
?>

Problem is that the pages they have visited can still be seen if they haven't closed there browser because it stores them in temp internet files. Is there a way to delete it from temp internet files, or make it get an updated version of the page each time they try to access it?

I think i've seen it done before in the (html) header, it sets a time on how long the page is valid for or something?

You can't control browser behavior and make it delete anything. You can try to set the page to not cache, which works with varying degrees of success.

I ended up finding this on the net:

header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Mon, 23 Jun 1986 12:00:00 GMT"); // This date is in the past.
header("Pragma: no-cache");

it works rather nicely.