Variations bulk edit JS error

When doing bulk edit on the variations for a product (on the product edit screen) the input boxes under the dotted line will throw a console error when editing. Once data is entered in the input boxes it "should" tick the checkboxes next to it.

Js code for that is in this file at the top
https://github.com/wp-e-commerce/WP-e-Commerce/blob/branch-4.0.0/wpsc-admin/js/product-variations.js