session logout???

[Anon]

I have alogout on my website - after logging out but then hittign back space and then refresh you can still see the content that should nit be possible to get to. How do I totally wipe out all sess varriables and destroy the session? What is wrong here?

<?php
// start session
session_start();

session_unregister("uname");
session_unregister("passwd");
session_unregister("repname");
session_unregister("loggedin");
session_unregister("repnum");
session_unregister("reptype");
session_unregister("root");
session_destroy();

readfile("logout.htm");

?>

[Anon]

From what I have read is this is a common problem, and the only way to really do it is to close the browser.
One work-around is to use a variable, let's say "loggedIn". When a person is logged in you set it to '1'. Once he clicks "logout" you set it to '0'. That should fix it.
Another way, is to just use the clock. Register a variable as something like "LoggedOutTime" and set the variable to the current time. If he hits the back button and "LoggedOutTime" < "the actual time" then the page has expired. That should do it.