var definition = {};
      var instance = basePrototype instanceof win.HTMLElement;
      var extended = tag['extends'] && (definition['extends'] = tag['extends']);

      if (basePrototype) {
        for (var z in basePrototype) {
          var proto = tag.prototype[z];
          var desc = instance ? Object.getOwnPropertyDescriptor(basePrototype, z) : basePrototype[z];
          if (proto) {
            for (var y in desc) {
              if (typeof desc[y] == 'function' && proto[y]) proto[y] = proto[y] = xtag.wrap(desc[y], proto[y]);
              else proto[y] = desc[y];
            }
            tag.prototype[z] = proto;
          }
          else if (desc) tag.prototype[z] = desc;
        }
      }

      definition['prototype'] = Object.create(
        extended ? Object.create(doc.createElement(extended).constructor).prototype : win.HTMLElement.prototype,
        tag.prototype
      );

      return doc.registerElement(_name, definition);