<%= form_for [:admin, @document_series.organisation, @document_series] do |form| %>
  <%= form.errors %>

  <%= form.text_field :name %>
  <%= form.text_field :summary %>
  <%= form.text_area :description, "class" => "previewable" %>
  
  <p class="warning">Warning: changes to document series appear instantly on the live site.</p>
  <%= form.save_or_cancel cancel: admin_organisation_path(@document_series.organisation) %>
<% end %>

<%= form_for [:admin, @document_series.organisation, @document_series] do |form| %>
  <%= form.errors %>

  <%= form.text_field :name %>
  <%= form.text_area :summary, rows: 2, class: 'js-summary-length-counting', data: { 'count-message-threshold' => 140, 'count-message-selector' => '.summary-length-info' } %>
  <div class="summary-length-info">Summary text should be 140 characters or fewer. <span class="count"></span></div>
  
  <%= form.text_area :description, "class" => "previewable" %>
  
  <p class="warning">Warning: changes to document series appear instantly on the live site.</p>
  <%= form.save_or_cancel cancel: admin_organisation_path(@document_series.organisation) %>
<% end %>

Add JS length warning to document series summary field in admin
Add JS length warning to document series summary field in admin
