var request = null;

function uncache(url){
	var d = new Date();
	var time = d.getTime();	
	return url + '&time='+time;
} 

/* 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.\nError 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.
	  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!");}
}