There are some bugs reported on that, but the solution I found was
- Make my application depend on jquery
- Edit your Gemfile and add:
- gem 'jquery-rails', '>= 1.0.12'
- rails generate jquery:install
By the way, I've seen several mentions of this, but since my Rails 3 already had it, I did not bother much. In your case, also make sure that your application.html.erb has these tags in your :
<%= csrf_meta_tag %>