function getXMLHttpRequest() {
          var request = false;
          try {
           request = new XMLHttpRequest();
          } catch(err1){
           try {
            request = new ActiveXObject('Msxml2.XMLHTTP');
           } catch(err2) {
            try {
             request = new ActiveXObject('Microsoft.XMLHTTP');
            } catch(err3) {
             request = false;
            }
           }
          }
          return request;
        }

        var r;
        r = getXMLHttpRequest();

        function get_menu(){
            if (r.readyState == 4) {
               if (r.status == 200) {
                document.getElementById('menu').innerHTML = r.responseText;
                }
             }
        }