// Validate Newsletter Form

//holds XMLHttpRequest instance
var xmlHttp = createXmlHttpRequestObject();

//holds Remote Server address
var serverAddress = "http://www.waters-edge.com/wp-content/themes/water/validate/validate.php";

// when set to true, display detailed error messages
var showErrors = true;

// initialize the validation requests cache
var cache = new Array();


// create XMLHttpRequest instance
function createXmlHttpRequestObject() 
{
	// store reference to the XMLHttpRequest object
	var xmlHttp;
	// this should work for all browsers except IE6 and older
	try	
	{
		// try to create XMLHttpRequest object
		xmlHttp = new XMLHttpRequest();
	}
	catch(e)
	{
		// assume IE6 or older
		var XmlHttpVersions = new Array("MSXML2.XMLHTTP.6.0","MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0","MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP");
		
		// try every id until one works
		for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++)
		{
			try
			{
				// try to create XMLHttpRequest object
				xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
			}
			catch(e) {} // ignore potential error
		}
	}
		// return the created object or display error message
		if(!xmlHttp)
			displayError("Error creating the XMLHttpRequest object.");
		else
			return xmlHttp;
}

// function to display error message
function displayError($message)
{
	// turn error display off
	showErrors = false;
	
	// ignore errors if ShowErrors is false
	if(showErrors)
	{
		// display error message
		alert("Error encountered: \n" + $message);
		// retry validation after 10 seconds
		var count= 0 
		while(count<4)
		{
			setTimeout("validate();", 10000);
			count++;
		}
	}
}

// validation for any form field
function validate(inputValue, fieldID)
{
	// only continue if xmlHttp isn't void
	if(xmlHttp)
	{
		// if received non-null parameters, add them to the cache in the form of a query string
		// to be sent to the server for validation
		if(fieldID)
		{
			// encode values for safely adding them to and HTTP request query string
			inputValue = encodeURIComponent(inputValue);
			fieldID = encodeURIComponent(fieldID);
			// add the value to the queue
			cache.push("inputValue=" + inputValue + "&fieldID=" + fieldID);
		}
		// try to connect to the server
		try
		{
			// continue only if the XMLHttpRequest object isn't busy
			// and the cache is not empty
			if ((xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
				 && cache.length > 0)
			{
				// get a new set of parameters from the cache
				var cacheEntry = cache.shift();
				// make a server request to validate the extracted data
				xmlHttp.open("POST", serverAddress, true);
				xmlHttp.setRequestHeader("Content-Type",
										 "application/x-www-form-urlencoded");
				xmlHttp.onreadystatechange = handleRequestStateChange;
				xmlHttp.send(cacheEntry);
			}
		}
		catch(e)
		{
			// display an error when failing to connect to the server
			displayError(e.toString() + " error validate");
		}
	}
}

// function that handles the HTTP response
function handleRequestStateChange()
{	
	// when readystate is 4, we read the server response
	if(xmlHttp.readyState == 4)
	{
		// continue only if HTTP status is "OK"
		if(xmlHttp.status == 200)
		{
			try
			{
				// read response
				readResponse();
			}
			catch(e)
			{
				// display an error when failing to connect to the server
				displayError(e.toString() + " failed to read response");
			}
		}
		else
		{
			// display error message
			displayError(xmlHttp.statusText);
		}
	}
}

// read server's response
function readResponse()
{
	// retrieve the server's response
	var response = xmlHttp.responseText;
	// server error?
	if (response.indexOf("ERRNO") >= 0 || response.indexOf("error:") >= 0 || response.length == 0)
		throw(response.length == 0 ? "Server error." : response);
	// get response in XML format ( assume the response is valid XML)
	responseXml = xmlHttp.responseXML;
	// get the document element
	xmlDoc = responseXml.documentElement;
	result = xmlDoc.getElementsByTagName("result")[0].firstChild.data;
	fieldID = xmlDoc.getElementsByTagName("fieldid")[0].firstChild.data;
	// find the HTML element that displays the error
	message = document.getElementById(fieldID + "-error");
	// show the error or hide the error
	message.className = (result == "0") ? "error" : "hidden";
	// call validate() again in case there are values left in the cache
	setTimeout("validate();", 500);
}