Using PHP sessions on each page.
At top of php pages have:
session_start();
Sessions work fine only when hit back browser button in IE get this warning:
Warning: Page has Expired
The page you requested was created using information you submitted in a form. This page is no longer available. As a security precaution, Internet Explorer does not automatically resubmit your information for you.
To resubmit your information and view this Web page, click the Refresh button.
