// JavaScript Document

// create a xml http request object
function CreateXmlHttpRequest()
{
	var httpRequest = null;
	try
	{
		httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
	}
	catch (e)
	{
		try
		{
			httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
		}
		catch (e)
		{
			httpRequest = null;
		}
	}
	
	if (!httpRequest && typeof XMLHttpRequest != "undefined")
	{
		httpRequest = new XMLHttpRequest();
	}
	//alert(httpRequest);
	return httpRequest;
}






// get url use via sync
function getUrlSync(url)
{
	return getUrl(url, false, null);
}

// get url use via async
function getUrlAsync(url, handleStateChange)
{
	return getUrl(url, true, handleStateChange);
}



function getUrlXMLResponseCallback(xmlHttpReq) {
	if(xmlHttpReq.responseXML == null) {
		alert("Error while processing your request.");
		return;
	}
	var root_node = getRootNode(xmlHttpReq);
	//alert (root_node);
	var return_code = getNodeValue(root_node, 'Return_code');
	//alert("return code " + return_code);

	if(return_code == 0) {
		var content = getContentNode(xmlHttpReq);
		/*if (content != null) {
			alert(content);
		}*/
		if(this.successCallback != null) {
			this.successCallback(xmlHttpReq, content, return_code, error_msg);
		}
	} else {
		var error_msg = getNodeValue(root_node, 'Message');
		if(this.successCallback != null) {
			this.successCallback(xmlHttpReq, content, return_code, error_msg);
		}
		
		
		//alert(error_msg)
	}
}

// execute on success
function execOnSuccess(stateChangeCallback)
{
	return function(xmlHttpReq)
		{
			if(xmlHttpReq.readyState == 4){
				if(xmlHttpReq.status == 200){
					
					stateChangeCallback(xmlHttpReq);
					//alert(xmlHttpReq + " " + xmlHttpReq.readyState + " " + xmlHttpReq.status);
					
				}else{
					//alert("xml http status is " + xmlHttpReq.status);
				}
			}else{
				//alert("xml http ready state is " + xmlHttpReq.readyState);
			}
			
		};
}


// get url
function getUrl(url, async, handleStateChange) {
	var xmlHttpReq = CreateXmlHttpRequest();
	if (!xmlHttpReq)
		return;

	if (handleStateChange)
	{
		xmlHttpReq.onreadystatechange = function()
			{
				handleStateChange(xmlHttpReq);
			};
	}
	else
	{
		xmlHttpReq.onreadystatechange = function() {;}
	}
	
	xmlHttpReq.open("GET", url, async);
	xmlHttpReq.send(null);
	//alert(xmlHttpReq);
}

// get url xml response
function getUrlXMLResponse(url, successCallback) {
	this.successCallback = successCallback;
	this.urlResponseCallback = getUrlXMLResponseCallback;
	getUrl(url, true, execOnSuccess(this.urlResponseCallback)) 
	
}






// post url
function postUrl(url, data, async, stateChangeCallback) { 
	var xmlHttpReq = getXmlHttpRequest(); 
	if (!xmlHttpReq)
		return;
	xmlHttpReq.open("POST", url, async);
	xmlHttpReq.onreadystatechange = function() {
			stateChangeCallback(xmlHttpReq);
		};
	// post url must set content-type with value application/x-www-form-urlencoded
	xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	xmlHttpReq.send(data);
	//alert ('url: ' + url + '\ndata: ' + data);
}

// post url xml response
function postUrlXMLResponse(url, data, successCallback) {
	this.successCallback = successCallback;
	this.urlResponseCallback = getUrlXMLResponseCallback;
	postUrl(url, data, true, execOnSuccess(this.urlResponseCallback))
}





// get a node value with specific tag name
function getContentNode(xmlHttpReq) {
	return xmlHttpReq.responseXML.getElementsByTagName('Content')[0];
}

// get a node value with tag name
function getNodeValue(obj,tag) {
	node=obj.getElementsByTagName(tag);
	
	if(node!=null && node.length>0) {
		return node[0].firstChild.nodeValue;
	}
	else {
		return null;
	}
}

// get the root object
function getRootNode(xmlHttpReq) {
	return xmlHttpReq.responseXML.getElementsByTagName('plist')[0];
}