var request = null;
var queryString;   //will hold the POSTed data

function sendData(url,handler){
    setQueryString();
    var url= url;
	var handleResponse = handler;
    httpRequest("POST",url,true,handleResponse,queryString);
}

function getData(url,handler){
    var url= url;
	var handleResponse = handler;
    httpRequest("GET",url,true,handleResponse);
}

/* 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);
    }
}

/* 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. */
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!");}
}

function setQueryString(){
    queryString="";
    var frm = document.forms[0];
    var numberElements =  frm.elements.length;
    for(var i = 0; i < numberElements; i++)  {
            if(i < numberElements-1)  {
                queryString += frm.elements[i].name+"="+
                               encodeURIComponent(frm.elements[i].value)+"&";
            } else {
                queryString += frm.elements[i].name+"="+
                               encodeURIComponent(frm.elements[i].value);
            }

    }
}