var xmlhttp;
var callBackFunction;

function Ajax_CallServerSideFunction(function_name, parameters, callback_function){
	Ajax_ShowLoader();

	callBackFunction = callback_function;
	xmlhttp = CreateXMLHttpRequest(callBack);
	var reqUrl;
	reqUrl = myAjaxUrl;
	var r = Math.random();
	var params = "";
	params += "ajax_request=true";
	params += "&function_name=" + function_name;

	params += "&parameters_count=" + parameters.length;
	var i;
	for(i = 0; i < parameters.length; i++){
		params  += "&p" + i + "=" + escape(parameters[i]);
	}
	
	reqUrl += "?rand=" + escape(r);
//	document.write(reqUrl);
//	alert(reqUrl);

  xmlhttp.open("POST", reqUrl, true);
	
//Send the proper header information along with the request
	xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	xmlhttp.setRequestHeader("Content-length", params.length);
	xmlhttp.setRequestHeader("Connection", "close");
	
  xmlhttp.send(params);
}

function Ajax_ShowLoader() {
  var ni = document.body;
  var newdiv = document.createElement('div');
  var divIdName = 'ajax_loader';
  newdiv.setAttribute('id',divIdName);
  newdiv.innerHTML = '<img src=\"aspajax/ajax-loader.gif\" />';
	newdiv.style.position = 'absolute';
	newdiv.style.top = document.body.scrollTop + 200 + 'px';
	newdiv.style.left = '50%';
	newdiv.style.border = '1px solid #999';
  ni.appendChild(newdiv);
}

function Ajax_HideLoader(divId) {
  var d = document.body;
  var olddiv = document.getElementById(divId);
  d.removeChild(olddiv);
}

function CreateXMLHttpRequest(handler) {
  var agt = navigator.userAgent.toLowerCase();
  var is_ie5 = (agt.indexOf('msie 5') != -1);
  var xmlhttp = null;
  try {
    xmlhttp = new XMLHttpRequest();
    try {
        // Fix for some version of Mozilla browser.
        http_request.overrideMimeType('text/xml');
    } catch(e) { }
    xmlhttp.onload = handler;
    xmlhttp.onerror = handler;
  } catch(e) {
    var control = (is_ie5) ? "Microsoft.XMLHTTP" : "Msxml2.XMLHTTP";
    xmlhttp = new ActiveXObject(control);
    xmlhttp.onreadystatechange = handler;
  }
  return xmlhttp;
}

function callBack(){
//	alert(xmlhttp.readyState);
	if(xmlhttp.readyState == 4){
//		alert(xmlhttp.status);
		if(xmlhttp.status == 200){
//			alert('Response: ' + xmlhttp.responseText);
			callBackFunction(xmlhttp.responseText);
			Ajax_HideLoader('ajax_loader');
		}
	}
}