PHP Reloading Pages With Post Variables
Fixing Document Expired with Firefox or Confirm Form Resubmission With Chrome
However, the php coder can work around the annoying message from the browser by adding a little code into the script. The example shows a couple of lines of code that can be added above session_start() in order to be able to go back and forth to the page when you post without any hangups.The 'private_no_expire' mode means that the client will not receive the expired header in the first place.
header('Cache-Control: no cache'); //no cache session_cache_limiter('private_no_expire'); // works //session_cache_limiter('public'); // works too session_start();