Rails Ajax Flash Messages

application.html.erb

    <div id="main" role="main">
      <div class="container">
         <div class="row">
          <div class="span12" id="top-div"> <!--! added "top-div" id to help with ajax -->
            <%= render 'layouts/messages' %>
            <%= yield %>
          </div>
        </div>
        <footer>
        </footer>
      </div> <!--! end of .container -->
    </div> <!--! end of #main -->

application_helper.rb

  def ajax_flash(div_id)
    response = ""
    flash_div = ""

    flash.each do |name, msg|
      if msg.is_a?(String)
        flash_div = "<div class=\"alert alert-#{name == :notice ? 'success' : 'error'} ajax_flash\"><a class=\"close\" data-dismiss=\"alert\">&#215;</a> <div id=\"flash_#{name == :notice ? 'notice' : 'error'}\">#{h(msg)}</div> </div>"
      end 
    end
    
    response = "$('.alert').remove();$('#{div_id}').prepend('#{flash_div}');"
    response.html_safe
  end
  

posts_controller.rb

  def vote
    vote = Vote.create(voteable: @post, creator: current_user, vote: params[:vote])

    respond_to do |format|
      format.html do
        if vote.valid?
          flash[:notice] = "Your vote was counted"
        else
          flash[:error] = "You can not vote on \"#{@post.title}\" more than once."
        end
        redirect_to :back
      end

      format.js do
        if vote.valid?
          flash.now[:notice] = "Your vote was counted"
        else
          flash.now[:error] = "You can't vote on that more than once"
        end
      end
    end
  end

vote.js.erb

$("#post_<%= @post.id %>_votes").html("<%= @post.total_votes %>");
<%= ajax_flash('#top-div') %>