How can I stop the browser back button using JavaScript?

Question

I am doing an online quiz application in PHP. I want to restrict the user from going back in an exam.

I have tried the following script, but it stops my timer.

Answer 1

history.pushState(null, null, document.URL);
window.addEventListener('popstate', function () {
    history.pushState(null, null, document.URL);
});

This javascript does not allow any user to go back (works in Chrome, FF, IE, Edge)