var http_request = false;

function xReqMake(url,activator)
	{
	http_request = false;

	if (window.XMLHttpRequest)
		{
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType)
			{
			http_request.overrideMimeType('text/xml');
			}
		}
	 else if (window.ActiveXObject)
		{
		try
			{
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
			}
		catch (e)
			{
			try
				{
				http_request = new ActiveXObject("Microsoft.XMLHTTP");
				}
			catch (e)
				{}
			}
		}

	if (!http_request)
		{
		//alert('no XMLHTTP instance created');
		return false;
		}
	
	http_request.onreadystatechange = activator;
	http_request.open('GET', url, true);
	http_request.send(null);
	}



function getModels()
	{
	if (http_request.readyState == 4)
		{
		if (http_request.status == 200)
			{
			var xmlItems = http_request.responseXML.getElementsByTagName('root').item(0).getElementsByTagName('item');
			var cntItems = xmlItems.length;

			var targetDiv = document.getElementById('ary_models');
			targetDiv.innerHTML = '';

			var listingElement = document.createElement('option');
			listingElement.setAttribute("value",0);
			listingElement.innerHTML = "-";
			targetDiv.appendChild( listingElement );


			for (var i=0; i<cntItems; i++)
				{
				var item = xmlItems.item(i);
				var listingElement = document.createElement('option');
				listingElement.setAttribute("value", item.getElementsByTagName('key').item(0).firstChild.nodeValue );
				listingElement.innerHTML = item.getElementsByTagName('value').item(0).firstChild.nodeValue;
				targetDiv.appendChild( listingElement );
				}

			}
		else
			{
			return true;
			//alert('problem with the request.');
			}
		}
	}






function conceal(element_id)
    {
    document.getElementById(element_id).style.display = 'none';
    }


function reveal(element_id)
    {
    document.getElementById(element_id).style.display = 'block';
    }