def wait_for_ajax
  counter = 0
  while page.evaluate_script('window.IN_REQUEST')
    counter += 1
    sleep(0.1)
    if (0.1 * counter) >= Capybara.default_max_wait_time
      raise "AJAX request took longer than " \
            "#{Capybara.default_max_wait_time} seconds."
    end
  end
end