pjax is awesome, but causes code within #content_for not to be rendered. Here's a solution.

app--helpers--application_helper.rb

module ApplicationHelper
  def content_for_or_pjax(name, &block)
    request.headers['X-PJAX'] ? capture(&block) : content_for(name, &block)
  end
end

app--views--foo--bar.html.erb

<%= content_for_or_pjax :javascript do %>
  <script type='text/javascript'>
    alert('Executing JS!');
  </script>
<% end %>