function checkUsernameAvailability(input)
{
	var url = '/assets/popups/checkUsernameAvailability.php?n='+input.value;
	var xmlHttp;
	try
	{
		// Firefox, Opera 8.0+, Safari
		xmlHttp=new XMLHttpRequest();
	}
	catch (e)
	{
		// Internet Explorer
		try
		{
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch (e)
		{
			try
			{
				xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
			}
			catch (e)
			{
				alert("Your browser does not support AJAX!");
				return false;
			}
		}
	}
	xmlHttp.onreadystatechange=function()
	{
		if(xmlHttp.readyState==4)
		{
			//Remove any previous checker details
			try{input.AVAILABILITY.parentNode.removeChild(input.AVAILABILITY);}catch(e){}
			//Now (re?)create the container for the availability message and icon
			input.AVAILABILITY = document.createElement('SPAN');	
			input.AVAILABILITY.style.fontSize = '0.9em';			
			var im = new Image();
			var text = '';
			if(xmlHttp.responseText)
			{
				im.src = '/assets/images/icons/ico_tick.gif';
				text = document.createTextNode(' username available');
				input.AVAILABILITY.style.color = 'green';
				//input.style.borderColor = 'green';
			}
			else			
			{
				im.src = '/assets/images/icons/ico_cross.gif';
				text = document.createTextNode(' username already taken');
				input.AVAILABILITY.style.color = 'red';
				//input.style.borderColor = 'red';
			}			
			input.AVAILABILITY.appendChild(im);
			input.AVAILABILITY.appendChild(text);
			input.parentNode.appendChild(input.AVAILABILITY);
		}			
	}
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
	return;
}
function filterHallSelector(countyDropdown)
{
	var selects = countyDropdown.form.getElementsByTagName('SELECT');
	for(var i=0;i<selects.length;i++)
	{
		if(selects[i].name=='fields[halls][]')
		{
			var select = selects[i];
			select.parentNode.className = select.parentNode.className.replace('hidden','');
			select.style.display = 'none';
			
			var im = new Image();
			im.src = '/assets/images/icons/ajax-loader.gif';
			select.parentNode.insertBefore(im,select);
			
			
			var url = '/assets/popups/getHallFilter.php?c='+countyDropdown.value;
			var xmlHttp;
			try
			{
				// Firefox, Opera 8.0+, Safari
				xmlHttp=new XMLHttpRequest();
			}
			catch (e)
			{
				// Internet Explorer
				try
				{
					xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
				}
				catch (e)
				{
					try
					{
						xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
					}
					catch (e)
					{
						alert("Your browser does not support AJAX!");
						return false;
					}
				}
			}
			xmlHttp.onreadystatechange=function()
			{
				if(xmlHttp.readyState==4)
				{
					//alert(xmlHttp.responseText);
					var hallNodes = xmlHttp.responseXML.firstChild.getElementsByTagName('hall');
					// Remove all the options from the hall selector					
					var i;
					for(i=select.options.length-1;i>=0;i--)
					{
						select.remove(i);
					}
					if(hallNodes.length>0)
					{
						for(var i=0;i<hallNodes.length;i++)
						{
							var optn = document.createElement("OPTION");
							optn.text = hallNodes[i].getAttribute('name');
							optn.value = hallNodes[i].getAttribute('id');
							select.options.add(optn);
						}
					}
					else
					{
						var optn = document.createElement("OPTION");
						optn.text = '-';
						optn.value = '';
						select.options.add(optn);
					}
					im.parentNode.removeChild(im);
					select.style.display = '';
					return;
				}			
			}
			xmlHttp.open("GET",url,true);
			xmlHttp.send(null);
			return;
		}
	}
}