AJAX - Default Code

function getXmlHttp() {
   var xmlHttp=-1;
   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 <SOME_FUNCTION>() {
   var xmlHttp;
   if (!(xmlHttp=getXmlHttp())) {return;}
   xmlHttp.onreadystatechange=function() {
      if (this.readyState==4&&this.status==200) {
         // stuff to do when request is complete
      }
   }
   /**
    * // for a POST request, use the following:
    * http_request.open('POST',<FILE_NAME>+"?time="+((new Date).getTime()),true);
    * http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    * http.setRequestHeader("Content-length", <PARAMS_LENGTH>);
    * http.setRequestHeader("Connection", "close");
    * http.send(<PARAMS>);
    */
   xmlHttp.open("GET",<FILE_NAME>+"?"+<PARAMS>+"&time="+((new Date).getTime()),true);
   xmlHttp.send(null);
}