Back Button Solutions

These headers will force the browser, and proxies if any, not to cache the page and force a new request to the server for that page:

  header("Cache-Control: private, must-revalidate, max-age=0");
  header("Pragma: no-cache");
  header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // A date in the past

add this between your HEAD tags

<META HTTP-EQUIV="Pragma" CONTENT="no-cache">