forms authentication time out

[chanko]

quick question

i have a web app which requires users to login to be able to access it
the login is made via forms authentication

as you all know, after "X" time of inactivity and then making a
request, the application will automatically redirect the user to the
login page, so said user can authenticate himself once again

there are 2 thing i need help in trying to achieve, or at least tell
me if possible or not


first off, is there any way, that once a user is logged on and that
session is lost due to inactivity, that instead of being redirected to
the login page, to be able to redirect them to a page where the user
is informed that they have been logged out because they were idle for
too long?

and also, how would one go about coding something like on online
banking sites (wamu comes to mind), where if you leave the page open
for too long without any activity, it'll pop up a confirm dialog box
where it asks you if you want to keep the session alive or not (don't
know if i explained myself fully on this)


thanks in advance
i really appreciate any light on this matter