Active user counting

[navaneethkn]

Hello

I need to count how many users are active in the website. Do you have any idea on this. I did using application variable. On session_start event in global.asax I am incrementing the application variable count and session_end event I am decreasing the count. But problem is when user closes browser no event will be fired. So I am not able to reduce the application variable count. It will show the old result. Do you know any method to handle this efficiently.

I am changing the application variable like this

Application.Lock();
Application["count"] = Application["count"]  + 1;
Application.UnLock();

I know lock method stops modifying the variable value at same time. But what will happen if two users request at same time ? Will the second request wait's till application variable get unlocked ? Or that request will be skipped ??

[kenobewan]

Asp.net is server side so for each person running the request it will run.