Hi all 
What i want to do is to create a custom select box added to the product details page and uppon selecting a value from this select box, product price will be updated based on a javascript calculation.
So there are 3 things i need to know.
Which is the best way to add the select box to the products detail page (i dont want to use a global products options), how can i add the javascript so based on the selection some function will be executed and finally how can i update the price based on the selection from the select box ?
I’ ve seen the fn_check_execeptions function but i want to use something custom and dont really know how to customize it.
Finally i’d like to know the best way in order not to loose any changes after an upgrade…
Thanks in advance