Control not transferring in JSP Ajax

<script type="text/javascript" language="javascript">  

     var index_x;
        function ajax_login(s,u,p)
        {   
            index_x=new XMLHttpRequest();
            var url="control.jsp?uid="+u+"&sid="+s+"&pwd="+p;
            index_x.onreadystatechange=show_ajaxlogin;
            index_x.open("GET",url,true);
            index_x.send(null);
        }
        function show_ajaxlogin()
        {
            if(index_x.readyState==4 ||index_x.readyState==200)
            {   
                    document.getElementById("forgot").innerHTML=index_x.responseText;
            }

        }

        </script>

When i call this function ajax_login(s,u,p) by button click, function is working but control is not transferring to control.jsp