I have a page called /add that you can add a Dog on and the form is in its own partial. I'm using Simple Form and Twitter Bootstrap. I added the files for the main Bootstrap but use a gem for simple_form to work with it just so you know.

DogsController

# new.js.erb (deleted new.html.erb)
def new 
 @dog = Dog.new

 respond_to do |format|
  format.js
 end
end

# create.js.erb
def create 
  @dog = current_user.dogs.new(params[:dog])

  respond_to do |format|
    if @dog.save
      format.html { redirect_to add_url, notice: 'Dog was successfully added.' }
      format.json { render json: @dog, status: :created, location: @dog}
      format.js
    else
      format.html { render 'pages/add' }
      format.json { render json: @dog.errors, status: :unprocessable_entity }
    end
  end
end

dogs/_form.html.erb

<%= simple_form_for(@dog, :remote => true) do |f| %>
  <%= render :partial => "shared/error_message", :locals => { :f => f } %>
    <%= f.input :name %>      
  <%= f.button :submit, 'Done' %>
<% end %>

This line: <%= render :partial => "shared/error_message", :locals => { :f => f } %>

Is for bootstrap so it renders the errors html correctly.

PagesController

def add

  respond_to do |format|
    format.html
  end
end

pages/add.html.erb

<div id="generate-form">
</div>          

dogs/new.js.erb

$("#generate-form").html("<%= escape_javascript(render(:partial => 'dogs/form', locals: { dog: @dog })) %>");

Now how would I get this to render the error partial as if it was still on my dogs/new.html.erb since its being created through AJAX? I don't need client side validations do I?