function ajaxFunction(){
var xmlHttp = null;
try{
  // Firefox, Opera 8.0+, Safari
  xmlHttp = new XMLHttpRequest(); 
  }
catch (e){
  // Internet Explorer
  try{
    xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e){
    try{
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
      }
    catch (e){
      alert("Your browser does not support AJAX!");
      return false;
      }
    }
  }     
  return xmlHttp;
}