var AJAX_SUCCESS		= 0;
var AJAX_INVALIDOBJECT		= 1;
var AJAX_INVALIDCALLBACK	= 2;
var AJAX_FAILEDOPEN		= 3;

function Ajax () {
	this.version		= '0.01';
	this.isAsync		= false;
	this.agent		= null;
	this.lastException	= '';

	if( typeof XMLHttpRequest != 'undefined' )
		this.agent = new XMLHttpRequest();

	if( this.agent == null ) {

		var axos = new Array(
//			'MSXML2.XMLHTTP.4.0',
			'MSXML2.XMLHTTP.3.0',
			'MSXML2.XMLHTTP',
			'Microsoft.XMLHTTP'
		);

		for( var i = 0; this.agent == null && i < axos.length; i++ ) {
			try {
				this.agent		= new ActiveXObject(axos[i]);

			} catch(e) {
				this.lastException	= e;
				this.agent		= null;
			}
		}
	}

	this.isValid	= callAjaxIsValid;
	this.get	= callAjaxGet;
	this.post	= callAjaxPost;
	this.open	= callAjaxOpen;
	this.request	= callAjaxRequest;
	this.response	= callAjaxResponse;
}

function AjaxResponse() {
	this.status	= 0;
	this.statusText	= '';
	this.headers	= new Array();
	this.body	= '';
	this.text	= '';
	this.xml	= '';
}

function AjaxRequest() {
	this.method	= 'GET';
	this.url	= '';
	this.headers	= new Array();
	this.body	= null;
	this.callback	= null;
}

function callAjaxGet( url, callback, headers ) {
	return this.open( 'GET', url, null, callback, headers );
}

function callAjaxIsValid() {
	return this.agent != null;
}

function callAjaxOpen( method, url, data, callback, headers ) {
	if (this.isValid()) {
		if (!method)	method		= 'GET';
		if (!data)	data		= null;
		if (callback)	this.isAsync	= true;

		if (this.isAsync) {
			if ( typeof callback != 'function' )
				return AJAX_INVALIDCALLBACK;
			this.agent.onreadystatechange = callback;
		}

		try {
			this.agent.open( method, url, this.isAsync );
		} catch(e) {
			this.lastException = e;
			return AJAX_FAILEDOPEN;
		}

		if ( method == 'POST' ) {
			this.agent.setRequestHeader( 'Connection', 'close' );
			this.agent.setRequestHeader( 'Content-type', 'application/x-www-form-urlencoded' );
		}

		if ( headers != null ) {
			for ( var header in headers ) {
				this.agent.setRequestHeader( header, headers[header] );
			}
		}

		this.agent.send(data);
		return AJAX_SUCCESS;
	}
	return AJAX_INVALIDOBJECT;
}

function callAjaxPost( url, data, callback, headers ) {
	return this.open( 'POST', url, data, callback, headers );
}

function callAjaxResponse() {
	if ( this.agent.readyState != 4 )
		return null;

	var res = new AjaxResponse();

	res.status	= this.agent.status;
	res.statusText	= typeof this.agent.statusText == 'undefined'
		? ''
		: this.agent.statusText;
	res.body	= typeof this.agent.responseBody == 'undefined'
		? ''
		: this.agent.responseBody;
	res.text	= typeof this.agent.responseText == 'undefined'
		? ''
		: this.agent.responseText;
	res.xml		= this.agent.responseXML == null
		? ''
		: this.agent.responseXML;

	var string = this.agent.getAllResponseHeaders();
	if (!string) string = '';

	var lines = string.split("\\n");
	for ( var i = 0; i < lines.length; i++ ) {
		var header = lines[i].split(": ");
		if(header.length >= 2) {
			var headername	= header.shift();
			var headervalue	= header.join(": ");

			res.headers[headername] = headervalue;
		}
	}

	return res;
}

function callAjaxRequest(req) {
	return this.Open(
		req.method,
		req.url,
		req.body,
		req.callback,
		req.headers
	);
}