/***********************************************\
* Original code taken from W3Schools:           *
* http://www.w3schools.com/ajax/ajax_source.asp *
\***********************************************/

var xmlHttp;
var functionToCall;

function ajax( url, parameters, returnFunction )
{
	xmlHttp = GetXmlHttpObject()
	
	if ( xmlHttp == null )
	{
		alert( "Your browser does not support AJAX!" );
		return;
	}
	
	if ( parameters != null )
		url += "?" + parameters;

	xmlHttp.onreadystatechange = ajaxStateChanged;
	functionToCall = returnFunction;
	
	xmlHttp.open( "GET", url, true );
	xmlHttp.send( null );
} 

function ajaxStateChanged()
{ 
	if ( xmlHttp.readyState == 4 )
		functionToCall( xmlHttp.responseText );
}

function GetXmlHttpObject()
{
	var xmlHttp = null;
	
	try
	{
		// Firefox, Opera 8.0+, Safari
		xmlHttp = new XMLHttpRequest();
	}
	catch ( e )
	{
		// Internet Explorer
		try
		{
			xmlHttp = new ActiveXObject( "Msxml2.XMLHTTP" );
		}
		catch ( e )
		{
			xmlHttp = new ActiveXObject( "Microsoft.XMLHTTP" );
		}
	}
	
	return xmlHttp;
}