Online exam web application

I am developing an online exam using JSP/Servlets which is nearing completion. I'm planning to add timer function for the entire exam that shows elapsed time in minutes. How do I implement this with a fool-proof technique to implement this, because using javascript would mean that the user can turn off the feature in the browser. Any help on this would be highly appreciated.

Which software is used in online exam?

ExamSoft: One of the commonly used online test software to guide students, prevent cheating and ease the accreditation process. Proview: The online exam software in India is an AI-powered remote proctoring solution to conduct online exams. It comes with the facility of assessment from anywhere anytime.

Record the time that the user started and finished on the server. The user will have to press a button to indicate that they've started the exam, which can trigger the server to stamp the start time; when the final answer is submitted, the server can record the total time taken.