Codeigniter System Changes

I would like exams management to be done on my system. For the exam management, I would like when a student is taking an exam, he/she cannot navigate away from the screen and if they do so whatever questions they had answered is submitted as the final mark and an email is sent to the admin to inform the admin that the student had navigated away from the exam screen and thus results submitted. Once the results are submitted the student is redirected away from the exam screen back to the dashboard.