JavaScript note: prototype, [[Protyotype]] and prototype property

JavaScript has two types of objects: function object and non-function object. Conceptually, all objects have a prototype (NOT A PROTOTYPE PROPERTY). Internally, JavaScript names an object's prototype as [[Prototype]].

There are two approaches to get any object (including non-function object)'s [[prototype]]: theObject.getPrototypeOf() method and the __proto__ property. The __proto__ property is supported by many browsers and Node.js. It is to be standardized in ECMAScript 6.

Only a function (a callable) object has the prototype property. This prototype property is a regular property that has no direct relationship with the function's own [[prototype]]. When used as a constructor ( after the new operator), the function's prototype property will be assigned to the [[Prototype]] of a newly created object. In a non-function object, the prototype property is undefined . For example,

var objectOne = {x: 5}, objectTwo = Object.create({y: 6});

Both objectOne and objectTwo are non-function objects therefore they don't have a prototype property.