# File lib/nanoc/extra/checking/checks/html.rb, line 9
    def run
      require 'w3c_validators'

      Dir[site.config[:output_dir] + '/**/*.{htm,html}'].each do |filename|
        results = ::W3CValidators::MarkupValidator.new.validate_file(filename)
        results.errors.each do |e|
          desc = e.message.gsub(%r{\s+}, ' ').strip
          self.add_issue(desc, :subject => filename)
        end
      end
    end