var request = null;

/* Initialize a request object that is already constructed */

function initReq(reqType,url,bool,respHandle){

    try{

        /* Specify the function that will handle the HTTP response */

        request.onreadystatechange=respHandle;

        request.open(reqType,url,bool);

        //if the reqType parameter is POST, then the

        //5th argument to the function is the POSTed data

        if(reqType.toLowerCase(  ) == "post") {

            request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");

            request.send(arguments[4]);

        }  else {

            request.send(null);

        }



    } catch (errv) {

        alert(

        "The application cannot contact "+

        "the server at the moment. "+

        "Please try again in a few seconds.\\n"+

        "Error detail: "+errv.message+". Error description:"+errv.description);

    }

}

/* Wrapper function for constructing a request object.

 Parameters:

  reqType: The HTTP request type, such as GET or POST.

  url: The URL of the server program.

  asynch: Whether to send the request asynchronously or not.

  respHandle: The name of the function that will handle the response.

  Any fifth parameters, represented as arguments[4], are the data a

  POST request is designed to send. */

function httpRequest(reqType,url,asynch,respHandle){

    //Mozilla-based browsers

    if(window.XMLHttpRequest){

        request = new XMLHttpRequest(  );

    } else if (window.ActiveXObject){

        request=new ActiveXObject("Msxml2.XMLHTTP");

        if (! request){

            request=new ActiveXObject("Microsoft.XMLHTTP");

        }

    }

    //very unlikely, but we test for a null request

    //if neither ActiveXObject was initialized

    if(request) {

        //if the reqType parameter is POST, then the

        //5th argument to the function is the POSTed data

        if(reqType.toLowerCase(  ) != "post") {
            initReq(reqType,url,asynch,respHandle);

        }  else {

            //the POSTed data

            var args = arguments[4];

            if(args != null && args.length > 0){

                initReq(reqType,url,asynch,respHandle,args);

            }

        }

    } else {

        alert("Your browser does not permit the use of all "+

              "of this application's features!");

    }

}