dynamic select home index view

gistfile1.rb

# app/views/home/index.html.haml
= collection_select(nil, :genre_id,  @genres,  :id, :name, {:prompt   => "Select a Genre"}, {:id => 'genres_select'})
%br
= collection_select(nil, :artist_id, @artists, :id, :name, {:prompt   => "Select an Artist"}, {:id => 'artists_select'})
%br
= collection_select(nil, :song_id, @songs, :id, :title, {:prompt   => "Select a Song"}, {:id => 'songs_select'})

:javascript
  $(document).ready(function() {
    $('#genres_select').change(function() {
      $.ajax({
        url: "#{update_artists_path}",
        data: {
          genre_id : $('#genres_select').val()
        },
        dataType: "script"
      });
    });
    $('#artists_select').change(function() {
      $.ajax({
        url: "#{update_songs_path}",
        data: {
          artist_id : $('#artists_select').val()
        },
        dataType: "script"
      });
    });
  });