No page Action, automatically exit the system in 5 minutes

The page has no action. after five minutes, the system automatically exits. I want the user to log on to the system. if there is no action within five minutes, the system automatically exits. How can we solve this problem?
How can I determine whether a page has no action?

Reply to discussion (solution)

Make a checklogin. php page
Inclde page in the page to determine whether the timeout exists

Session_start ();
Header ("content-type: text/html; charset = utf-8 ");
// Timeout Time. unit: Seconds. set this parameter to 10 minutes.
$ Timeout = 600;
$ Now = time ();
If ($ now-$ _ SESSION ['session _ time'])> $ timeout)
{
// Timeout.
Unset ($ _ SESSION ['clientid']);
}
Else
{
// No timeout.
$ _ SESSION ['session _ time'] = time ();
}
If (empty ($ _ SESSION ["clientID"])
{
Echo"