In my application, I use session to store some postback value. So, I solved
the standard ASP.NET session timeout  issue by doing these:

1. In web.config,  I used <sessionState> and set it to 12 hours with mode
set to "inproc"
2. On IIS win2003 level,  I set it "Idle recycle" value from default 20 min
to 12 hours under Application Pool.

It works fine. However, on AJAX .NET side,  I changed the
"AsyncPostBackTimeout" value in <asp:ScriptManager>, however this is more
like the "httpruntime" in web.config. It has nothing to do with session
timeout.

With the "AsyncPostBackTimeout" changed, when I tested this, I left the page
for 30 min and come back.  Click on one of my AJAX controls (just regular
page control, i.e. without Ajax it will postback), and I got the  NULL
javascript error.  Am I missing something?  Please help.

Thanks.

NB