How does session timeout work?

[msgopala]

If you have a keep alive it does exactly that. It keeps the session alive so of course it will not time out.

Thank you! I was under the impression that it keeps the page alive only till the user interacts with it. 

So am I right in saying that even if the user is interacting with the page, the page will timeout if the keepalive is not set. 

How do I determine inactiveness and then expire the page?

Thank you for your help.