g === 'body' || closeTag === 'html') {
        return null;
      }
      var content = nestableContent(openTag, closeTag);
      if (content === null) { return null; }
      if (content !== '#text') {
        content = '<' + content + '></' + content + '>';
      }
      return tagStackToHtml(stack, '</' + closeTag + '>' + content);
    }

    function check(openTag, closeTag, body, result) {
      var content = nestableContent(openTag, closeTag);
      var element = body.getElementsByTagName(openTag)[0];
