var Ajax = {};

Ajax.reduceQuery = function(args)	{
	var chunks = [];
	for(var i in args) if (typeof args[i] != 'function') chunks.push(i + '=' + encodeURIComponent(args[i]));
	return chunks.join('&');
}

Ajax.getQuery = function(url)	{
	var query = {};


	var chunks = url.replace(/.*?(\?|$)/, '').split('&');
	for(var index in chunks)	{
		var i = chunks[index];
		if(!(typeof i == 'string')) continue
		var pair = i.split('=');
		query[pair[0]] = decodeURIComponent(pair[1]);
	}
	return query;
}

Ajax.stateChangeHandler = function(ok, err, extract)	{
	if(this.readyState == 4)
	{
		if(this.status == 200 || this.status == 0)	{if(ok) ok(extract(this))}
		else{if(err)err(this.status + ': ' + this.statusText)}
	}
}

Ajax.request = function(method, url, data, ok, err, format)
{
	if(typeof data == 'function')	{
		format = err;
		err = ok;
		ok = data;
		data = null;
	}
	
	if(err && typeof err == 'string')	{
		format = err;
		err = null;
	}
	
	if(data) data = Ajax.reduceQuery(data);
	
	if(method == 'GET' && data) url += '?' + data;
	
	var req = new XMLHttpRequest();
	
	var extract = Ajax.extractText;
	if(format == 'json' || format == 'js') extract = Ajax.extractJs;
	else if(format == 'xml') extract = Ajax.extractXml;
	
	req.onreadystatechange = function()	{Ajax.stateChangeHandler.apply(req, [ok, err, extract])}
	
	try{
		req.open(method, url, true);
	}catch(e){
		if(err)err(e);
	}

	if(method == 'POST')req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	if(format == 'xml') req.overrideMimeType('text/xml');
	
	req.send(data);
}

Ajax.get = function(url, args, ok, err, format)	{
	Ajax.request('GET', url, args,
		ok, err, format) 
}

Ajax.post = function(url, args, ok, err, format)	{
	Ajax.request('POST', url, args,
		ok, err, format) 
}

Ajax.extractText = function(http)	{
	return http.responseText;
}

Ajax.extractJs = function(http)	{
	return eval(http.responseText);
}

Ajax.extractXml = function(http)	{
	return http.responseXML;
}