taiwan_city/app/views/china_city/data/index.html.erb

<%-
  province = '440000'
  city = '440300'
  district = '440305'
  provinces  = ChinaCity.list
  cities     = ChinaCity.list(province)
  districtes = ChinaCity.list(city)
%>
<div class='rails-helper city-group'>
  <%= select_tag :province, options_for_select(provinces, province) , prompt: '--省份--', class: ['city-select', 'city-province'] %>
  <%= select_tag :city    , options_for_select(cities, city)        , prompt: '--城市--', class: ['city-select', 'city-city'] %>
  <%= select_tag :district, options_for_select(districtes, district), prompt: '--地区--', class: ['city-select', 'city-district'] %>
</div>

<div class='html-tag city-group'>
  <select class='city-select city-province'>
    <option>--省份--</option>
    <%= options_for_select(ChinaCity.list, province) %>
  </select>
  <select class='city-select city-city'>
    <option>--城市--</option>
    <%= options_for_select(cities, city) %>
  </select>
  <select class='city-select city-district'>
    <option>--地区--</option>
    <%= options_for_select(districtes, district) %>
  </select>
  </div>