function ajax_update(element_id, url, parameter)
{
	var x = new Ajax.Updater(element_id,url, {parameters: parameter , evalScripts: true});
}

function ajax_update_complete(element_id, url, parameter, complete_function)
{
	var x = new Ajax.Updater(element_id,url, {parameters: parameter , evalScripts: true, onComplete:complete_function});
}

function update_cart_qty(artwork_id, price)
{
	var qty_id = 'qty-' + artwork_id;
	var subtotal_id = 'subtotal-' + artwork_id;
	var qty = document.getElementById(qty_id);
	alert(price);

	ajax_update(subtotal_id, 'update_cart.php', {item_id: artwork_id, qty:qty.value, price:price});
}