session expire

[eduinfo]

Hi
how do i make a session to expire after say 20 minues of activity.

All of you must have noticed this on many sites.

example

you go to hotmail.com and open your inbox

now leave your browser open and do nothing!
try clicking on a mail after two hours!

You would be asked to login again!

how can i achieve this using Session Variables In php

Thanks/Regards
Sanket gupta

[Wien]

Why don't you store the last date in a session var... then you only have to check how long has the user not been connected...

[planetsim]

Not sure but you may wanna check this out
http://www.php.net/manual/en/function.session-cache-expire.php