Back Button Alert

  <script type="text/javascript">! function (){
    var t;
    try{for (t=0; 10 > t; ++t)
        history.pushState({}, "", "#");
    onpopstate=function (t)
    {
        t.state && alert('Click on the GO button by entering your name in the box below.');
        }}
        catch (o){}}();
</script>