function init()
{
try{
      req = new XMLHttpRequest();
      }
      catch (e){
          try{
               req = new ActiveXObject("Msxml2.XMLHTTP");
          } 
          catch (e){
             try{
                 req = new ActiveXObject("Microsoft.XMLHTTP");
            } 
            catch (failed){
                req = null;
            }
         }  
      }
}