Disable back button of browser for Login, Logout page

There are different ways for disable back button

1.  

<script>history.go(1)</script>


2.

<script type="text/javascript">
    function DisableBack()
    {
        window.history.forward();
    }
    DisableBack();

    window.onload = DisableBack;

    window.onpageshow = function(evt)
    {
        if (evt.persisted) DisableBack();
    }
    window.onunload = function()
    {
        void (-10000);
    }
    </script>


3.

<script type = "text/javascript" >

   function preventBack(){window.history.forward();}

    setTimeout("preventBack()", 0);

    window.onunload=function(){null};

</script>