How to set the elements selected in an autocomplete field

I have users pick genres from an autocomplete field. This field is in the edit view of the profile, so I have accepts_nested_attributes_for :genres in the Profile model. Also, Genre and Profile have a has_and_belongs_to_many association with one another. My question is how do you take t开发者_开发问答he genres that the user picks and set them for that user's profile? What kind of controller code would I need? Would the code go in the profiles or genres controller?

I'm using this for autocomplete: http://loopj.com/jquery-tokeninput/ I've already prepopulated the genres table and hooked up the script to the text field. Right now when a user types, the autocomplete successfully displays suggestions. Now I want to update the database with the selected genres. This database is a join table between genres and profiles. How and where do I do this?

To sum up, I want to save the association between the profile id and the ids of the genres selected into the join table when I click the button in the profile edit view. Right now I get this error:

ActiveRecord::UnknownAttributeError in ProfilesController#update

unknown attribute: genre
Rails.root: /rubyprograms/dreamstill

app/controllers/profiles_controller.rb:18:in `update'
app/controllers/profiles_controller.rb:17:in `update'

Here's my profile edit view:

<%= form_for(:profile, @profile, :url => {:controller => "profiles", :action => "update"}, :html => { :multipart => true, :method => :put }) do |f| %>
...
<%= f.fields_for :genre do |g| %>
 <div class="field">
      <%= g.label :name, "Genres" %><br />
      <%= g.text_field :name, :id => 'genre_field' %>
  </div>
<% end %>
...
<div class="action">
  <%= f.submit :profile, :value => "Update Profile" %>
</div>
<% end %>

Check this page http://loopj.com/jquery-tokeninput/demo.html

In this page clicking on submit alerts ids of the element, as per my understanding.

The script below in head does it

<script type="text/javascript">  
  $(document).ready(function() {  
    $("input[type=button]").click(function () {  
     alert("Would submit: " + $(this).siblings("input[type=text]").val());   
    });
   });
</script>

This mat help you.. Basically there is an hidden text field which stores ids of the selected elements