# File lib/jpmobile/filter.rb, line 94
    def convert_text_content(document)
      document.children.each do |element|
        if element.kind_of?(Nokogiri::XML::Text)
          unless element.parent.node_name == "textarea"
            # textarea 以外のテキストなら content を変換
            element.content = filter(element.content, @@internal, @@external)
          end
        elsif element.node_name == "input" and ["submit", "reset", "button"].include?(element["type"])
          # テキスト以外でもボタンの value は変換
          element["value"] = filter(element["value"], @@internal, @@external)
        elsif element.children.any?
          # 子要素があれば再帰的に変換
          element = convert_text_content(element)
        end
      end

      document
    end