// requirements: mozxpath.js (for Mozilla browsers)

function ASXML() {

	var xmlHttpRequest;
	var callbackCode;
	var handle = -1;
	var self = this;
	var isAsync = true;

	this.getHandle = function() {
		return self.handle;
	}

	this.setHandle = function(newHandle) {
		self.handle = newHandle;
	}

	// public functions
	this.xmlResponse = function() {
		return self.xmlHttpRequest.responseXML;
	}

	this.textResponse = function() {
		return self.xmlHttpRequest.responseText;
	} 

	this.statusCode = function() {
		return self.xmlHttpRequest.status;
	}

	this.statusText = function() {
		return self.xmlHttpRequest.statusText;
	} 

	this.setCallback = function(callback) {
		self.callbackCode = callback;
	}

	this.getCallback = function()	{
		return self.callbackCode;
	}

	this.getXML = function(url)	{
		self.xmlHttpRequest = getBrowserHTTPRequest(); // get request object
		self.xmlHttpRequest.onreadystatechange = readyStateChange;
		self.xmlHttpRequest.open("GET", url, isAsync);
		self.xmlHttpRequest.send(null);
	}

	this.postXML = function(url,postData) {
		self.xmlHttpRequest = getBrowserHTTPRequest(); // get request object
		self.xmlHttpRequest.onreadystatechange = readyStateChange;
		self.xmlHttpRequest.open("POST", url, self.isAsync);
		self.xmlHttpRequest.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
		self.xmlHttpRequest.send(postData);
	}

	// private functions
	var getBrowserHTTPRequest = function () {
		var httpRequestAccess = null;

		if(window.XMLHttpRequest) // is a moz / IE7 browser
		{
			httpRequestAccess = new XMLHttpRequest();
		}
		else if(window.ActiveXObject) // is a IE4,5,6 browser
		{
			httpRequestAccess = new ActiveXObject("Microsoft.XMLHTTP");
		}

		return httpRequestAccess;
	} 

	var readyStateChange = function () {
		var HTTP_REQUEST_UNINITIALISED = 0;
		var HTTP_REQUEST_LOADING = 1;
		var HTTP_REQUEST_LOADED = 2;
		var HTTP_REQUEST_INTERACTIVE = 3;
		var HTTP_REQUEST_COMPLETE = 4;
		var REQUEST_STATUS_OK = 200;
		var REQUEST_STATUS_NOTFOUND = 404;

		if(self.xmlHttpRequest)	{
			if (self.xmlHttpRequest.readyState == HTTP_REQUEST_COMPLETE) {
				if(self.callbackCode)	{
					self.callbackCode(self.xmlHttpRequest.status == REQUEST_STATUS_OK); //send true back, if the doc loaded ok, false otherwise
				}
			}
		}
	}

	// clears a dropdownlist
	this.clearDDL = function(ddl, startTxt, startVal) {

		//clear out dropdownlist
		while (ddl.childNodes.length >0){
			ddl.removeChild(ddl.childNodes[0]);
		}

		//insert initial value (if provided)
		if(startTxt != ""){
		    var o = document.createElement("Option");
		    o.innerHTML = startTxt;
		    o.value = startVal;
		    ddl.appendChild(o);
        }
	}

	// repopulates a dropdownlist
	this.populateDDL = function(ddl, nodes, startTxt, startVal) {

		//clear out dropdownlist
		this.clearDDL(ddl,startTxt,startVal);

		//populate the dropdown
		for(var i = 0; i < nodes.length; i++) {
			var op=document.createElement("option");
			var v,t;

			v = nodes[i].getElementsByTagName("value")[0].childNodes[0].nodeValue;
			t = nodes[i].getElementsByTagName("name")[0].childNodes[0].nodeValue;

			op.value = v;
			op.innerHTML = t;
			ddl.appendChild(op);
			
			//if just 'startVal' provided, then assume that we want the dropdown to default to this value (if it exists)
			if(startTxt == "" && startVal != 0){
			    if(v == startVal){ddl.options[i].selected = true;}
			}
		}
	}
}