code: function(nodes, root, tagName, combinator) {
        var uTagName = tagName.toUpperCase();
        var results = [], h = Selector.handlers;
        if (nodes) {
          if (combinator) {
            // fastlane for ordinary descendant combinators
            if (combinator == "descendant") {
              for (var i = 0, node; node = nodes[i]; i++)
                h.concat(results, node.getElementsByTagName(tagName));
              return results;
            } else nodes = this[combinator](nodes);
            if (tagName == "*") return nodes;
          }
          for (var i = 0, node; node = nodes[i]; i++)
            if (node.tagName.toUpperCase() === uTagName) results.push(node);
          return results;
        } else return root.getElementsByTagName(tagName);
      }
docs: TOKEN FUNCTIONS