在使用devise的Rails 5应用程序中，我需要使用new.js.erb文件来更新注册视图和控制器中的select标记。我似乎不能弄清楚为什么我的new.js.erb文件不工作。
我尝试在控制器中使用respond_to，如下所示：

registrations-controller.rb

def new
   super 
   @cities = CS.get(:us,params[:state]) 
   respond_to do |format|
     format.js { render '/new.js.erb' }# layout: false }          
     format.html 
   end
 end

字符串

new.html.erb

<%= form_for(resource, as: resource_name, url: registration_path(resource_name), :remote => true) do |f| %>
   <div class="signup-input-container">
     <div class="field">
        <%= f.text_field :firstname, autofocus: true, autocomplete: "firstname", placeholder: "First name", class: "signup-input-container--input" %>
     </div>
     <div class="field">
        <%= f.select :state, options_for_select(CS.states(:us).map { |code, name| [name, code] }),{:prompt => "State"}, {:class => "signup-input-container--input", :id => "state-picker"} %>
     </div>
     <div class="field">
        <%= f.select :city, options_for_select([]),{}, {:class => "signup-input-container--input", :id => "city-picker"} %> 
     </div>
  </div>
<% end %>

型

new.js.erb

var city = document.getElementById("city-picker");

  while (city.firstChild) city.removeChild(city.firstChild);

  var placeholder = document.createElement("option");
  placeholder.text = "Choose a city";
  placeholder.value = "";
  city.appendChild(placeholder);

 <% @cities.each do |c| %>
   city.options[city.options.length] = new Option('<%= c %>');
 <% end %>

型

main.js

var state = document.getElementById("state-picker");
  state.addEventListener("change", function() {
     $.ajax({
        url: "/states?state=" + state.value,
        type: "GET"
     })
  })

型
我期待这将创建选择标记选项与我的城市数组在我的控制器。有谁知道怎么让它工作吗？