/**
 * Browser-independent [A]JAX call
 * 
 * @param {String} locationURL an URL to call, without parameters
 * @param {String} [parameters=null] a parameters list, in the form 
 *        'param1=value1&param2=value2&param3=value3'
 * @param {Function(XHMLHTTPRequest, Object)} [onComplete=null] a function that
 *        will be called when the response (responseText or responseXML of 
 *        XHMLHTTPRequest) will be received
 * @param {Boolean} [doSynchronous=false] make a synchronous request (onComplete
 *        will /not/ be called)        
 * @param {Boolean} [doPost=false] make a POST request instead of GET        
 * @param {Object} [dataPackage=null] any object to transfer to the onComplete 
 *        listener
 * @return {XHMLHTTPRequest} request object, if no exceptions occured
 */
function makeRequest(locationURL, parameters, onComplete, doSynchronous, doPost, dataPackage) {
	var http_request = false;
	try {
		http_request = new ActiveXObject("Msxml2.XMLHTTP");
	} catch (e1) {
		try {
			http_request= new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e2) {
			http_request = new XMLHttpRequest();
		}
	}

	//if (http_request.overrideMimeType) { // optional
	//  http_request.overrideMimeType('text/xml');
	//}
 
	if (!http_request) {
		alert('Cannot create XMLHTTP instance');
		return false;
	}
  
	if (onComplete && !doSynchronous) {
		completeListener = function() { 
			if (http_request.readyState == 4) {
				if (http_request.status == 200) {
					onComplete(http_request, dataPackage)
				}
			}
		};
		http_request.onreadystatechange = completeListener;
	}
 
	//var salt = hex_md5(new Date().toString());
	if (doPost) {
		http_request.open('POST', locationURL, !doSynchronous);
		http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		http_request.setRequestHeader("Content-length", parameters.length);
		http_request.setRequestHeader("Connection", "close");
		http_request.send(parameters);
	} else {
		http_request.open('GET', locationURL + (parameters ? ("?" + parameters) : ""), !doSynchronous);
		//http_request.open('GET', './proxy.php?' + parameters +
		// "&salt=" + salt, true);
		http_request.send(null);                        
	}
	return http_request;
}