how to prevent rails displaying flash message twice

Question

I am using bootstrap alert to style rails flash messages, but i don't know why it happens

 def render_flash_msgs
    unless @_flash_rendered
        @_flash_rendered = true
        render 'shared/flash_msgs'
    end
 end

  # return html class for flash_key
  def bootstrap_class_for(flash_key)
     flash_key == :notice ? 'alert-info' : "alert-#{flash_key}"
  end

I can't post image, so i can just post the html result sources

  <div id="flash">
  <div class="alert" title="Notice">
    <button class="close" data-dismiss="alert">×</button>
    <div>Post was successfully updated.</div>
  </div> 
  <!-- dont know why it showed again under the alert block -->
  <p id="notice">Post was successfully updated.</p>

Edit :-------------------------------------------------- here is my form

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

  .field
    = f.label :title
    = f.text_field :title
  .actions = f.submit 'Save'

here is my flash page -----------------------------------

#flash
  - flash.each do |type, message|
    .alert class=bootstrap_class_for(type)
      button.close data-dismiss="alert"
        | ×
      div = message 

Answer 1

Sounds like your alerts are displayed once in layout and once in form. Please show us layout and post _form partial.