code: def every_html_doc
        every_page do |page|
          if (block_given? && page.html?)
            if (doc = page.doc)
              yield doc
            end
          end
        end
      end
docs: Pass every HTML document that the agent parses to a given block.
  
   @yield [doc]
     The block will be passed every HTML document parsed.
  
   @yieldparam [Nokogiri::HTML::Document] doc
     A parsed HTML document.
  
   @see http://nokogiri.rubyforge.org/nokogiri/Nokogiri/HTML/Document.html