What is best & Secure timer for online test application in asp.net C# Ajax timer or Jquery Timer?

Question

I am creating a new application in asp.net 4.0 which contains an online test module, and the application is supposed to handle 10-20k students at a time. Now my confusion is what should i use here, which should be:

1. Secure , I don't want kids to turn off javascript in browser and get unlimited time for test.
2. Which should not overhead the network traffic.
3. Which have a pause/start function with try limits.
4. Should fire the needed function on server side after time is complete (eg redirect to another page via c# function)

Any help and example code is appreciated.

Regards

Alok Sharma

FYI: I am not experienced with jquery.

Answer 1

If the security of timer is critical you should not fully rely on javascript code. I would recommend to keep the time when test is started for a specific user on both sides, server and client. Then implement javascript timer which periodically synchronizes with web server. When user completes the test and sends results to the server you should check if the timeout is elapsed on server side.

In additional I would add a logic in order to ban the possibility to open the page and start test without javascript enabled.