We have a client with a simplified e-commerce system based around the e-commerce module. In the order form on the Checkout Page is a "Shipping Destination" field which is intended to be used to calculate the weight based freight charge for the order.
How can I trigger a refresh of the freight field in the order and in the display when the customer changes the Shipping Destination field in the order form. I'm guessing some form of custom client-side validation is required but I'm at a loss how to implement this.
I would prefer the displayed order details changed on the fly but if I have to save the partially completed details and trigger a page refresh then that will be ok too.
Can anyone offer some suggestions or code from a similar requirement?