$(document).ready(function() {
	
	$(".qty").change(function() {
		var product_id = this.id.substr(3, this.id.length-3);
		var new_product_total = parseInt(this.value)*parseInt($("#price"+product_id).val());
		if (isNaN(new_product_total))
			$("#multiply_price"+product_id).html('bad value');
		else
			$("#multiply_price"+product_id).html(new_product_total.toString());
			
		var total_price = 0;
		$(".mulPrice").each(function() {
			var prod_price = parseInt($(this).html());
			if (!isNaN(prod_price))
				total_price+=prod_price;
		});
		$("#total").html('$'+total_price.toString());
	});
	
});