Quick fix for my quiz website

I run a quiz website. Everything works well, except one small bug. The test won't mark by itself when time is up , it only marks when the user clicks on end exam. Our goal is to make the test mark by itself.
Please let me know if you can do this (ASAP).
Thanks for your time.

https://braindocacademytests.com/#!/exam/7ef8c0a471a8730a295c8f5e6fe24b9b/123