__proto__ VS. prototype in JavaScript

Question

This figure again shows that every object has a prototype. Constructor function Foo also has its own __proto__ which is Function.prototype, a

Answer 1

Another good way to understand it:

var foo = {}

/* 
foo.constructor is Object, so foo.constructor.prototype is actually 
Object.prototype; Object.prototype in return is what foo.__proto__ links to. 
*/
console.log(foo.constructor.prototype === foo.__proto__);
// this proves what the above comment proclaims: Both statements evaluate to true.
console.log(foo.__proto__ === Object.prototype);
console.log(foo.constructor.prototype === Object.prototype);

Only after IE11 __proto__ is supported. Before that version, such as IE9, you could use the constructor to get the __proto__.