# Populating dropdowns REST-style **URL:** \ **Category:** Rails\ **Created:** [May 19, 2008, 9:52pm UTC](https://www.ruby-forum.com/t/populating-dropdowns-rest-style/138053 "2008-05-19T21:52:03Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![ahead](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c77e96/32.png) [@ahead](https://www.ruby-forum.com/u/ahead)\ **Post date:** [May 19, 2008, 9:52pm UTC](https://www.ruby-forum.com/t/populating-dropdowns-rest-style/138053/1 "2008-05-19T21:52:03Z")
Resource A and B are nested. In the form for C, I need to populate a dropdown of B:s depending on the value of A. Trying to be RESTful, my approach is to have an onchange-handler on the A dropdown which calls the index action of B and redraws the B dropdown using RJS and a partial. My concern is that because the RJS and partial should generate a select-helper for editing C, the code in the “B domain” (controller, RJS, partial) needs to be C-aware which feels ugly… Does anybody have an alternative design which makes this cleaner somehow? Another (perhaps silly) question. If I use the form builder object in the partial for B, it seems hard to reuse it from RJS because I don’t have a form builder object there. Or should I skip the form builder for the B dropdown and use the instance variable instead? (Similar to how scaffolding in earlier version of Rails did it) Wow, that’s a long and somewhat strange post. I’m impressed that you made it to the end! 😉 ---
**Author:** ![ahead](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c77e96/32.png) [@ahead](https://www.ruby-forum.com/u/ahead)\ **Post date:** [May 20, 2008, 12:24am UTC](https://www.ruby-forum.com/t/populating-dropdowns-rest-style/138053/2 "2008-05-20T00:24:21Z")
Hi, I’ve only just finished writing a tutorial on exactly this: > **[frozenplague.net](http://frozenplague.net/2008/05/20/updating-a-select-box-based-on-another/)** > > This domain may be for sale! ## Enjoy. Appreciated my help? Reccommend me on Working With Rails [http://workingwithrails.com/person/11030-ryan-bigg](http://workingwithrails.com/person/11030-ryan-bigg)