# File lib/mechanize/util.rb, line 54
      def detect_charset(src)
        tmp = NKF.guess(src || "<html></html>")
        if RUBY_VERSION >= "1.9.0"
          enc = tmp.to_s.upcase
        else
          enc = NKF.constants.find{|c|
            NKF.const_get(c) == tmp
          }
          enc = CODE_DIC[enc.intern]
        end
        enc || "ISO-8859-1"
      end