tracks/app/views/notes/create.js.erb

<% if @saved -%>
  TracksPages.hide_errors();
  add_note();
  clear_form();
<% else -%>
  TracksPages.show_errors(html_for_error_messages());
<% end -%>

function add_note() {
  $('div#notes').append(html_for_note_summary());
  $('#empty-n').hide();
}

function clear_form() {
  $('#new-note').hide();
  $('#edit-note-form').clearForm();
}

function html_for_error_messages() {
  return "<%= js_error_messages_for(@note) %>";
}

function html_for_note_summary() {
  return "<%= @saved ? js_render('notes_summary', {}, @note) : "" %>";
}