function ajax(url, id) {
      var xmlHttp=null;
      try { // Firefox, Opera 8.0+, Safari, IE7
        xmlHttp=new XMLHttpRequest();
      }
      catch(e) {// Old IE
         try {
            xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
         }
         catch(e) {
            alert ("Your browser does not support XMLHTTP!");
            return;  
         }
      }
      xmlHttp.onreadystatechange=function() {
         if (xmlHttp.readyState==4) {
               try {
                  if (document.getElementById(id).type == "text" || document.getElementById(id).type == "hidden") {
                     document.getElementById(id).value=xmlHttp.responseText;
                  } else {
                    document.getElementById(id).innerHTML=xmlHttp.responseText;
                  }
   
               } catch(e) {
                  alert('err');
               }
         }
      }

      xmlHttp.open("GET",url,false);
      xmlHttp.setRequestHeader('If-Modified-Since', 'Wed, 15 Nov 1995 00:00:00 GMT');
      xmlHttp.send(null);

}