mixed

Hi, In asp there is a session timeout function that allows the session to end after the session is INACTIVE for x seconds/minutes ! How do i do this in php ? Is there a way to open a php page in internet expl. without having a url/adress bar or a back and forward button , if so how do i go to work? I asked this before, but say for instance - the user is busy on a secure page , but without logging out he enters another url in the address bar.The session of my page , does it end or does the session carry to the next page ? If so how can i stop it ? thanks , shaun!