PHP: how to set the timeout for the system
<p>How to detect user action, from a website then we set the timeout for the system?</p>

<p>For example, user login to the system, and the user do not do any action in the system for 30 minutes, then the system makes auto-logout for the user, then how can I know whether the user did any actions (like move the mouse, type the keyboard...)?</p>
