Please come all to help me solving my session timeout dilemma by adjustify the available code to fit my requirements.

I have been advised to follow the following link in order to perform Session-Timeout operation using JQuery:
http://www.codeproject.com/Articles/711196/Session-Time-Out-Warning-Message-Using-jQuery-in-A
However, the suggested link doesnt consider many things that I need and I tried my best to adjust this code to fulfill my requirements but I failed. Thus, I would highly appreciate helping me adjust the given code as per project structure, as following:
1. I have a master page "MasterPage.master" which all other aspx files are belonging to.
2. I want to call the "initSession()" function after the user make success logging through the form LogonScreen.aspx
3. I need the session total time to be 30 minutes and to cover all the project aspx forms. I mean if the time s ...