function clone(proto) {
    function Dummy() { }
 
    Dummy.prototype             = proto;
    Dummy.prototype.constructor = Dummy;
 
    return new Dummy(); //等价于Object.create(Person);
}
 
var me = clone(Person);

function proto(object) {
    return !object?                null
         : '__proto__' in object?  object.__proto__
         : /* not exposed? */      object.constructor.prototype
}