response_helpers.rb

module ResponseHelpers
  def response_dom
    html = response.try(:body) || page.try(:body)
    $stderr.puts "WARNING: No response HTML!" if html.blank?

    Nokogiri::HTML(html)
  end
end

World(ResponseHelpers)

web_steps.rb

Then /^"([^\"]*)" should be disabled$/ do |element|
  e = response_dom.search("//input[@id='#{ element }']").first ||
      response_dom.search("//input[@name='#{ element }']").first ||
      response_dom.search("//input[contains(@value, '#{ element }')]")

  if defined?(Spec::Rails::Matchers)
    e.should_not be_nil
    e.attr('disabled').to_s.should eql('disabled')
  else
    assert_not_nil e
    assert_equal 'disabled', e.attr('disabled').to_s
  end
end