function add_to_cart(product_id) {
	var size_element = $('ring_size');
	var ring_size = 0;
	if (size_element)
		ring_size = size_element.value;
	
	var cart = unescape(readCookie('cart'));
	if (cart == 'null') cart = '';
	
	// make sure the product/size combo doesn't already exist in the cart.
	if (cart && cart.length > 0) {	
		var items = cart.split(',');
		if (items.length > 0) {
			for (var i = 0; i < items.length; i++) {
				item_info = items[i].split(':');
				if (item_info[0] == product_id) {
					if (ring_size > 0) {
						if (item_info[2] == ring_size) {
							document.location = '/cart';
							return;
						}
					}
					else {
						document.location = '/cart';
						return;
					}
				}
			}
		}
	}
	
	if (cart && cart.length > 0)
		cart += ',';
	else
		cart = '';
	
	cart += product_id + ':1';
	if (ring_size > 0)
		cart += ':' + ring_size;
	
	setCookie('cart', cart, 30);
	
	window.location = "/cart";
	
}

function alternate_ship_bill_status() {
	var fields = $$('#shipping_details input, #shipping_details select');
		
	if ($('shipping_same_as_billing').checked) {
		$('shipping_details').className = 'disabled';
		for (var i = 0; i < fields.length; i++) {
			fields[i].disabled = true;
		}
	}
	else {
		$('shipping_details').className = '';
		for (var i = 0; i < fields.length; i++) {
			fields[i].disabled = false;
		}
	}
}