如何添加损坏的提交按钮？

Question

我想在民意调查和两个提交按钮中找到可能答案的表格。第一个传递所有文本字段，第二个传递其中一个字段为nil导致验证错误。这是我的_form.html.haml文件：

= form_for [@poll, @question] do |f|
  - if @question.errors.any?
    #error_explanation
      %h2= "#{pluralize(@question.errors.count, "error")} prohibited this question from being saved:"
      %ul
        - @question.errors.full_messages.each do |msg|
          %li= msg

  .field
    = f.label :title
    = f.text_field :title
  %p
    = f.label :kind
  .radio
    -@kind_options.each do |option|
      %label
        =f.radio_button :kind, option[1]
        =option[0]
  =f.fields_for :possible_answers do |c|
    %p
      =c.text_field :title, class: "form-control", placeholder: "Enter a possible answer"
  .actions
    = f.submit 'Save', class: "btn btn-primary"

  - x = f
  = x.hidden_field :kind, :value => nil
  = x.submit 'Corrupted Sumbit Button', class: "btn btn-primary"

如果我提交x或f似乎没有区别：即使我在单选按钮中选择它并点击f.submit按钮，kind也是空白。如何解决这个问题？