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

This is the way I could it accomplish it. Weirdly changing the window.location didn't worked out fine in chrome and safari. Happens that the location.hash doesn't create an entry in the history for chrome and safari. So you will have to use the pushstate. This is working for me in all browsers.

    history.pushState({ page: 1 }, "title 1", "#nbb");
    window.onhashchange = function (event) {
        window.location.hash = "nbb";

    };