不更新动态选择导轨

Question

我有问题，我实现动态选择，但不更新ciudades。

有人占用了这段代码吗？

我的代码。

autos.coffee：

$ ->
  $(document).on 'change', '#regiones_select', (evt) ->
    $.ajax 'update_ciudades',
      type: 'GET'
      dataType: 'script'
      data: {
        region_id: $("#regiones_select option:selected").val()
      }
      error: (jqXHR, textStatus, errorThrown) ->
        console.log("AJAX Error: #{textStatus}")
      success: (data, textStatus, jqXHR) ->
         console.log("Dynamic region select OK!")

汽车控制器：

    class AutosController < ApplicationController
   before_action :set_auto, only: [:show, :edit, :update, :destroy]

 def index
    @autos = Auto.all
 end


  def show
  end


  def new
    @regiones = Region.all
    @ciudades = Ciudad.where("region_id = ?", Region.first.id)
    @auto = Auto.new
  end


  def edit
  end


  def create
    @auto = Auto.new(auto_params)
    respond_to do |format|
      if @auto.save
        format.html { redirect_to @auto, notice: 'Auto was successfully created.' }
        format.json { render :show, status: :created, location: @auto }
      else
        format.html { render :new }
        format.json { render json: @auto.errors, status: :unprocessable_entity }
      end
    end
  end


  def update
    respond_to do |format|
      if @auto.update(auto_params)
        format.html { redirect_to @auto, notice: 'Auto was successfully updated.' }
        format.json { render :show, status: :ok, location: @auto }
      else
        format.html { render :edit }
        format.json { render json: @auto.errors, status: :unprocessable_entity }
      end
    end
  end


  def destroy
    @auto.destroy
    respond_to do |format|
      format.html { redirect_to autos_url, notice: 'Auto was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private

    def set_auto
      @auto = Auto.find(params[:id])
    end


    def auto_params
       params.require(:auto).permit(:region_id, :ciudad_id,)
    end
end

_form.html.erb：

<%= form_for @auto, url: {action: "create"}, html: {method: "post"} do       |f| %>
  <%= f.select :region_id, options_for_select(@regiones.collect { |region|
[region.region.titleize, region.id] }, 1), {}, { id: 'regiones_select' } %>
  <%= f.select :ciudad_id, options_for_select(@ciudades.collect { |ciudad|
[ciudad.ciudad.titleize, ciudad.id] }, 0), {}, { id: 'ciudades_select' } %>
  <%= f.submit "Go!" %>
<% end %>

new.html.erb：

<h1>New Auto</h1>

<%= render 'form' %>

<%= link_to 'Back', autos_path %>

代码执行工作......

问候