Simple 2 way constrains between selectboxes Version 1.1

A customer have some options which are related and contains constrains.
Say: You can only combine the car vw with one color green .
This is a simple implementation of such rules, using only jQuery .
Version 1.1: Small changes after 1st live implementation.


You can actually have more elements bound to a data-type !

The model only needs to define the constrains seen from one of the options:
I only "tell" which colors exists for which car. Code will "turn constrains around" and generate the "color to car" constrains.
Two data-attributes on the select element are used to enforce constrains:
data-type : The type of constrain (like car )
data-bound : Which data-type is it bound to? (like color )

Util: Automated method call with a complete matrix