Changing the $but_onclick process

Hi All

I have written a small addon to the cart_status.tpl file which advises the customer how much more they have to spend to get free delivery.

The function works fine when the page is refreshed, however, when an item is added to the basket only the mini-checkout is refreshed.

What is driving this dynamic resfresh, how can I force my function to refresh?

Has anyone got any suggestions?

When I put my function and code within the cart_status.tpl file the data updates along with the mini-cart.

Does anyone know what is driving this?