Preventing the backbutton not to go to the previous URL when the control is in focus inside a textbox, textarea or radio button in any browser

While developing a website in Asp.net MVC4, I noticed that when my control is in focus inside a text-box or text-area, which are read only, it is moving to the parent of the current URL. In order to solve it i had written a JQuery below which will prevent the back to the parent URL in any browser and in any web developing programming languages.


    $(document).keydown(function(e) {
        var doPrevent;
        if (e.keyCode == 8) {
            var d = e.srcElement || e.target;
            if (d.tagName.toUpperCase() == 'INPUT' || d.tagName.toUpperCase() == 'TEXTAREA') {
                doPrevent = d.readOnly || d.disabled;
            }
            else
                doPrevent = true;
        }
        else
            doPrevent = false;

        if (doPrevent)
            e.preventDefault();
    });


Enjoy!..........