/*
This is a barebones Ajax library written by Tim Tripcony (http://www.timtripcony.com).
*/
var Ajax = function() {
    var transport; // private variable, will store the request object
    var callback; // private variable, will store the function to run against the returned data
    var errorHandler; // private variable, will store the function to run if the request fails
    try {
        transport = new XMLHttpRequest(); // first preference, supported in all major browsers except I.E.
    } catch (e) {
        try {            
            transport = new ActiveXObject('Msxml2.XMLHTTP'); // newer versions of I.E.
        } catch (e) {
            try {            
                transport = new ActiveXObject('Microsoft.XMLHTTP'); // older versions of I.E., last resort
            } catch (e) {
                alert(e.description); // inform the user their browser doesn't support Ajax
            }
        }
    }
    var processStateChange = function() { // private function, runs whenever the request object's state changes
        if (transport.readyState === 4) { // indicates the request is completed
            if (transport.status === 200) { // indicates the request was successful
                if (callback) { // skip if no callback function was defined
                    callback(transport); // run the function defined in the options parameter and pass a handle to the request object
                }
            } else {
                if (errorHandler) {
                    errorHandler(transport); // run the function defined in the options parameter and pass a handle to the request object
                }
            }
        }
    };
    transport.onreadystatechange = processStateChange; // bind the private function to all state changes
    return { // return an object with public members that still have access to the private members
        request: function (options) {
            callback = options.onSuccess || null; // if defined, sets the private variable, otherwise replaces undefined with null
            errorHandler = options.onFailure || null; // if defined, sets the private variable, otherwise replaces undefined with null
            transport.open(options.method || 'GET',options.url,options.async || false); // establish the URL connection
            transport.send(options.postData || null); // retrieve the data
        }
    };
}(); // runs the anonymous function and sets the Ajax variable to the returned object

// Crockford's object function (http://javascript.crockford.com/prototypal.html)
function object (o) {
	function F(){}
	F.prototype = o;
	return new F();
}

/*
The following extends the Google AJAXSLT library (http://code.google.com/p/ajaxslt/).
It allows both the XML and the XSL to be retrieved from the server in a single call.
*/
var Xslt = function() {
	var xmlDoc;
	var xslDoc;
	var onXmlLoaded;
	var onXslLoaded;
	var NestedAjax = object(Ajax); // allows us to handle a nested Ajax call with a separate object

	return {
		transform: function (options) {
			onXmlLoaded = options.onXmlLoaded || null;
			onXslLoaded = options.onXslLoaded || null;
			Ajax.request({
				method: 'POST',
				url: options.xmlUrl,
				async: true,
				onSuccess: function (xmlObject) {
					if (!!onXmlLoaded) {
						onXmlLoaded(xmlObject);
					}
					xmlDoc = xmlParse(xmlObject.responseText);
					NestedAjax.request({
						method: 'POST',
						url: options.xslUrl,
						async: true,
						onSuccess: function (xslObject) {
							if (!!onXslLoaded) {
								onXslLoaded(xslObject);
							}
							xslDoc = xmlParse(xslObject.responseText);
							options.callback(xsltProcess(xmlDoc,xslDoc));
						}
					});					
				}
			});
		}
	};

}();