Validation in twitter/bootstrap modal rails 3.2 - ruby-on-rails-3

Question

I am trying to get validation to return in my modal using rails 3.2,twitter/bootstrap and formtastic, but I am at a loss as to how to do this.
Below is a quick sample of what my modal and form look like. In the model I require firstname and lastname. If the user hits 'submit' without putting in a firstname or lastname, it immediately takes the user to my actual registration page and notifies them of what is missing.
But I would like it to return to this modal and let the user know what is missing. How do I accomplish this?
:In my header, this is how I bring up the modal:
=link_to 'Register', "#new_registration_modal", :data => { :toggle => "modal",:backdrop => "static" }
#app/views/subscribers/registration/_new_modal.html.haml
#new_registration_modal.modal.hide.fade
.modal-header
Some Text
.modal-body
Some Text
=semantic_form_for(:subscriber, :as => resource_name, :url => registration_path(resource_name),:html => { :class => "form-inline" } ) do |f|
=f.input :email
=f.input :firstname
=f.input :lastname
=f.input :password
=f.input :password_confirmation
=f.submit
.modal-footer
Some Text

Answer 1

I have found a solution working for my side (using simple_form), maybe can help you:
I want to add a new client inside a modal from another controller.
The view of the modal controller:
<div id="client_modal" class="modal hide fade" tabindex="-1" role="dialog" aria-labelledby="client_modal_label" aria-hidden="true">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h3 id="client_modal_label">Create new client</h3>
</div>
<div class="modal-body">
<%= simple_form_for Client.new, html: {"data-type" => :json}, remote: true do |f| %>
<div id="error_explanation" style="display:none;"></div>
<div class="form-inputs">
# the inputs
# ... and "closing" the modal
The client_controller.create:
def create
# save the data
if #client.save
respond_to do |format|
format.html { redirect_to anagrafe_index_path, :notice => "Client create!"}
format.json { render json: #client, status: :created, location: #client }
end
else
respond_to do |format|
format.html { render :action => 'new'}
format.json { render json: #client.errors.full_messages, status: :unprocessable_entity }
end
end
end
The js.coffee where the modal is raised:
$ ()->
$("form.new_client").on "ajax:success", (event, data, status, xhr) ->
$("form.new_client")[0].reset()
$('#client_modal').modal('hide')
$('#error_explanation').hide()
$("form.new_client").on "ajax:error", (event, xhr, status, error) ->
errors = jQuery.parseJSON(xhr.responseText)
errorcount = errors.length
$('#error_explanation').empty()
if errorcount > 1
$('#error_explanation').append('<div class="alert alert-error">The form has ' + errorcount + ' errors.</div>')
else
$('#error_explanation').append('<div class="alert alert-error">The form has 1 error.</div>')
$('#error_explanation').append('<ul>')
for e in errors
$('#error_explanation').append('<li>' + e + '</li>')
$('#error_explanation').append('</ul>')
$('#error_explanation').show()