javascript - Dynamic Select Menu in Rails -

i'm trying implement dynamic select menu in rails application, following youtube video #88 .

i set video, javascript doesn't work should.

my view code: _form.html.erb

<div class="field">   <%= f.label :cliente_id %><br>   <%= f.collection_select :cliente_id, cliente.order(:name), :id, :name, include_blank: true %> </div> <div class="field">   <%= f.label :projeto_id %><br>   <%= f.grouped_collection_select :projeto_id, cliente.order(:name), :projetos, :name, :id, :name, include_blank: true %> </div> 

relatos.coffe ->

jquery ->    projetos = $('#relato_projeto_id').html()   $('#relato_cliente_id').change ->     cliente = $('#relato_cliente_id :selected').text()     options = $(projetos).filter("optgroup[label='#{cliente}']").html()     if options        $('#relato_projeto_id').html(options)     else       $('#relato_projeto_id').empty() 

the page seems ok, no errors, when list cliente(client) should list projects listed him, keeps showing projects there no jquery @ all.

the starting of code jquery when should jquery. person said before, see.