Andrew found this code on the product pages of a fairly popular automotive e-commerce website. It's called whenever an 'attribute' of a product (size, color, etc.) is selected or changed by the user.
The main focus of this code is to update a concatenation of the values of all currently selected attributes which are stored in a hidden form input field. Once it has done that, it hands off to another function to make an AJAX request with this concatenated value as a parameter.