var xml = '';

function makeXMLRequest(url, parameters, routine) {
	xml = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
		xml = new XMLHttpRequest();
		if (xml.overrideMimeType) {
			xml.overrideMimeType('text/plain');
		}
	} else if (window.ActiveXObject) { // IE
		try {
			xml = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				xml = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}
	if (!xml) {
		alert('Cannot make connection to server. Please upgrade or use a different browser.');
		return false;
	}
		
	eval ("xml.onreadystatechange = "+routine);
	xml.open("POST", url, true);
	xml.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	xml.setRequestHeader("Content-length", parameters.length);
	xml.setRequestHeader("Connection", "close");
	xml.send(parameters);
		
	return xml;
}

function updateQuantity(){
	if (quantity_xml.readyState != 4) return false;
	if (quantity_xml.status != 200) return false;
	var text = quantity_xml.responseText;
	quantity_xml = false;
	if (!text){document.getElementById('quantity').innerHTML = ""; return false;}
	var arr  = text.split(",");
	var total = 0;
	for (var h in arr)
		if ((arr[h] != null) && (arr[h] != '')) total += parseInt(arr[h]);	
	document.getElementById('quantity').innerHTML = '('+total+')';
}


function getQuantity(){
	quantity_xml = makeXMLRequest('/cart/item_quantity/', '', updateQuantity);
}