Modify JavaScript Shopping Cart Script

Hi, This project requires you to modify an existing jquery shopping cart script. It needs to be able to specify for certain products options, for example a product might have 3 size options, small, medium +5 and large +10, depending on which is selected this needs to be reflected in the price. The solution has to only be in javascript and jquery, this should be an easy mod, and more projects will be rewarded after completion. Smart Cart2 this is the script that needs modifying [login to view URL] Each product in created with a hidden input with product img and description ect, your code will have to do something similar that allows me to generate product options for certain products as an extra input, then your code should detact this and display in a dropdown the product options, then depending on which is selected, that becomes the price. This is a rush order so a winner will be chosen quickly, and will be required to complete the work within a day. Bids £30-50