AJAX - Default Code

function getXmlHttp() {
   var xmlHttp;
   try {
      xmlHttp=new XMLHttpRequest();
   } catch (e) {
      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;
}
function do_ajax() {
   var params=""; // Add request parameters here
   var file=""; // Add the name of the request file here
   var xmlHttp;
   if (!(xmlHttp=getXmlHttp())) {return;}
   xmlHttp.onreadystatechange=function() {
      if (this.readyState==4&&this.status==200) {
         // Add code to be executed when the request is complete and successful
      }
   }
   var time=(new Date).getTime();
   /**
    * // for a post request, use the following:
    * xmlHttp.open('POST',file+"?time="+time,true);
    * xmlHttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    * xmlHttp.setRequestHeader("Content-length",params.length);
    * xmlHttp.setRequestHeader("Connection","close");
    * xmlHttp.send(params);
    */
   xmlHttp.open("GET",file+"?"+params+"&time="+time,true);
   xmlHttp.send(null);
}