Tomcat session idle does not work due to Ajax

In my web application(jsp/servlet) there is a web page which create Ajax request periodically to grab the latest data from the server.This page is the main page which is always open once user log in to the system while other pages open in new browser windows(due to user events).

I have to invalidate the user session which idle for more than 30 minutes. For that I use Tomcat session timeout feature. But the thing is most of the time users session which are idle for 30 min are not invalidated.

But some time user sessions are invalidated by Tomc开发者_开发技巧at after 30 min. I think this is because the main page send Ajax request periodically without idling the session.

I want to know that is Tomcat can't identified the auto generated request from user event and invalidate session properly.Please give an ideas on this,it will be very helpful for me.

Dinesh

I don't think you have a choice here - if Tomcat identifies and ignores the AJAX request, you'll lose the functionality it provides for you