javascript's __proto__ and prototype explained

prototypes.js

/**
 * __proto__ and prototype
 * - the __proto__ property the instance's 'parent' up the prototype chain
 * - the prototype property refers what new instances of the type will have their __proto__ set to, i.e. what will be the new instance's 'parent' up the prototype chain
 */

/* Given */
function Object () {}
Object.prototype = {
  __proto__: null
};

/* And */
function Function () {}
Function.prototype = {
  __proto__: Object.prototype
};

/* When objects are created */
var o = new Object();
/* their __proto__ property is set to Object.prototype, to make them Objects */
o.__proto__ = Object.prototype;

/* When new functions are created */
function F () {}
/* their __proto__ property is set to Function.prototype, to make them Functions */
F.__proto__ = Function.prototype;

/* New instances of F should also be Objects, so Fs prototype refers Object.prototype as its __proto__ */
F.prototype = {
  constructor: F,
  __proto__ : Object.prototype
};

/* When new Fs are created */
var f = new F();
/* their __proto__ is set to F.prototype, to make them Fs */
f.__proto__ = F.prototype;