code: function recurse(node) {
      // first navigate to the first sibling
      if (node.previousSibling) recurse(node.previousSibling);
      // then add the string representation of the nodes ('backward' recursion)
      switch (node.nodeType) {
        case 8: // comment
          html += "<!--" + node.nodeValue + "-->";
          break;
          // case 10: // doctype: jsDom does not know doctype as previousSibling.
      }
    }
docs: add previous siblings