Asp.net Prevent Browser Back Button

 <script type="text/javascript" language="javascript">
window.history.forward(1);
document.attachEvent("onkeydown", my_onkeydown_handler);
function my_onkeydown_handler()
{
switch (event.keyCode)
{
case 116 : // F5;
event.returnValue = false;
event.keyCode = 0;
window.status = "We have disabled F5";
break;
}
}
</script>
protected void Page_Load(object sender, EventArgs e)
   {
     HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
     HttpContext.Current.Response.Cache.SetNoServerCaching();
     HttpContext.Current.Response.Cache.SetNoStore();
   }