function CNetLoader()
{
  this.Url = null;
  this.onLoad = null;
  this.onError = null;
  this.responseXML = null;
  this.responseText = null;
  this.ErrorDesc = null;
}

CNetLoader.prototype = {
 	GetTransport: function() {
		var transport = null;
		if(window.XMLHttpRequest) {
			transport = new XMLHttpRequest();
		} else {
			if(window.ActiveXObject) {
				try {
					transport = new ActiveXObject("Msxml2.XMLHTTP");
				} catch (err) {
					transport = new ActiveXObject("Microsoft.XMLHTTP");
 				}
			}
		}
		return transport;
	},

	LoadXMLDoc: function(Url, PostParams, onLoad, onError) {
		this.Url = Url;
		this.onLoad = onLoad;
		this.onError = onError;
		var Request = this.GetTransport();
		Request.open('POST', this.Url, true);
		Request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
		var obj = this;
		Request.onreadystatechange = function() { obj.OnReadyState(Request); }
		Request.send(PostParams);
	},
	
	OnReadyState: function(Request) {
		if(Request.readyState == 4) {
			//собственно в сл строке и происходит ошибка, т.е. при получении ответа
			if(Request.status == 200 || Request.status == 0) {
				//обрабатываем успешную загрузку
			} else {
				//обрабатываем ошибку
			}
		}
	}
}