I used to organize js binding based on the controller (https://github.com/pivotal/jelly), but found that it is better to base it on the template.

There are a few reasons:

1. It makes more conceptual sense. The javascript relates to html (which is generated by the template), not a controller action.

2. You will probably want to reuse templates across different controllers. Also partial templates can have reusable behavior.

3. It is easier to move between the associated javascript + template

4. Refactoring is easier, especially with html gotten via AJAX