var ajax = {};
ajax.xhr = {};

ajax.xhr.Request = function(url, params, callback, method)
{
	this.url = url;
	this.params = params;
	this.callback = callback;
	this.method = method;
	this.send();
}

ajax.xhr.Request.prototype = {
	getXMLHttpRequest: function()
	{
		if (window.ActiveXObject)
		{
			try
			{
				return new ActiveXObject("Msxml2.XMLHTTP");
			}
			catch (e)
			{
				try
				{
					return new ActiveXObject("Microsoft.XMLHTTP");
				}
				catch (e1)
				{
					return null;
				}
			}
		}
		else if (window.XMLHttpRequest)
		{
			return new XMLHttpRequest();
		}
		else
		{
			return null;
		}
	},
	send: function()
	{
		this.req = this.getXMLHttpRequest();		//req 프로퍼티에 XMLHttpRequest 객체를 저장

		var httpMethod = this.method ? this.method : 'GET';
		if (httpMethod != 'GET' && httpMethod != 'POST')
		{
			httpMethod = 'GET';
		}

		var httpParams = (this.params == null || this.params == '') ? null : this.params;
		var httpUrl = this.url;
		if (httpMethod == 'GET' && httpParams != null)
		{
			httpUrl = httpUrl + "?" + httpParams;
		}

		this.req.open(httpMethod, httpUrl, true);
		this.req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		var request = this;
		this.req.onreadystatechange = function() {
			request.onStateChange.call(request);		//XMLHttpRequest객체의 readyState값이 바뀔 때 이 객체(Request객체)의 onStateChange함수 호출
		}

		this.req.send(httpMethod == 'POST' ? httpParams : null);
	},
	onStateChange: function()
	{
		this.callback(this.req);					//이 객체의 callback 프로퍼티에 할당된 함수를 호출한다. 이때 인자로 this.req 객체를 (XMLHttpRequest객체를)전달한다.
	}
}

escape: function(value) {
	return escape(value).replace(/\+/g, '%2B');
}