Question

I have a model “categories”:
t.string :c1
t.string :c2
t.string :c3

---

A category could be: Ferrari, red, maxspeed.
I created some categories, and I want to built a form where I can choose how to send a category:
If I choose c1 then I want to choose c2 ONLY from all the categories who have c1 like my choise; for example If I choose “ferrari” I can only choose the colours avaiable for that type of car. How can I do that, starting from this code?

<div class="field">
    <%= f.label :brand %>
    <%= select (:request, :brand, Category.all.collect  {|category| [category.c1]}) %>
</div>
<div class="field">
    <%= f.label :color %>
    <%= select (:request, :color, Category.all.collect  {|category| [category.c2]}) %>
</div>
<div class="field">
    <%= f.label :maxspeed %><
    <%= select (:request, :maxspeed, Category.all.collect  {|category| [category.c3]}) %>
</div>

Answer 1

I’ve found two solutions to build a chained menu:

from railcasts: http://railscasts.com/episodes/88-dynamic-select-menus
javascript: http://www.dynamicdrive.com/dynamicindex1/chainedmenu/chainedmenu.html#note