Very simple class alternative

k.js

/*

var Foo = {
  __proto__: K,
  method: function () {}
};

var Bar = {
  __proto__: Foo
};

var bar = Bar.new();

Bar.isPrototypeOf(bar) === true;
Foo.isPrototypeOf(bar) === true;
K.isPrototypeOf(bar) === true;

typeof bar.method === 'function';

*/

var K = {
  constructor: function () {},

  new: function () {
    var o, ret;

    o = Object.create(this);
    ret = o.constructor.apply(o, arguments);

    if (ret && typeof ret === 'object') {
      return ret;
    }

    return o;
  }
};