Using $_POST information only once
<p>I have some information which gets passed from a form and needs to be used once and only once.  I can collect it nicely from $_POST but I'm not sure which is the "best" way to ensure that I can only use it once, i.e. I want to avoid the user pressing F5 repeatedly and accessing the function more than once.  </p>

<p>My initial thought was to set a session variable and time the function out for a set period of time.  The problem with that is thay could have access to the function again after the set period has elapsed.</p>

<p>Better ideas welcomed!</p>
