JAVASCRIPT中的作用域和原型链，应该算是难点了，要好好多学学，练练

<script>
console.log(Object.getOwnPropertyNames(Object.prototype));
function Empty() {}
console.log(Function.prototype, Function.__proto__);
console.log(Object.prototype, Object.__proto__);
function F() {};
F.prototype = {
  a: function() {}
};
F.prototype.constructor = F;
console.log(F.prototype, F.__proto__);
var o = new Object();
console.log(o.prototype, o.__proto__);
var i = new F();
console.log(i.prototype, i.__proto__);
</script>