Test prototypes of various objects and the various means to access them. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS ('').__proto__ is String.prototype PASS (0).__proto__ is Number.prototype PASS (true).__proto__ is Boolean.prototype PASS (Symbol()).__proto__ is Symbol.prototype PASS ([]).__proto__ is Array.prototype PASS ({}).__proto__ is Object.prototype PASS (new Date).__proto__ is Date.prototype PASS (new Error).__proto__ is Error.prototype PASS (new Number).__proto__ is Number.prototype PASS (new Object).__proto__ is Object.prototype PASS (new String).__proto__ is String.prototype PASS Array.prototype.__proto__ is Object.prototype PASS Date.prototype.__proto__ is Object.prototype PASS Number.prototype.__proto__ is Object.prototype PASS Object.prototype.__proto__ is null PASS String.prototype.__proto__ is Object.prototype PASS Array.__proto__ is Object.__proto__ PASS Date.__proto__ is Object.__proto__ PASS Number.__proto__ is Object.__proto__ PASS String.__proto__ is Object.__proto__ PASS Object.getPrototypeOf('') is String.prototype PASS Object.getPrototypeOf(0) is Number.prototype PASS Object.getPrototypeOf(true) is Boolean.prototype PASS Object.getPrototypeOf(Symbol()) is Symbol.prototype PASS Object.getPrototypeOf([]) is Array.prototype PASS Object.getPrototypeOf({}) is Object.prototype PASS Object.getPrototypeOf(new Date) is Date.prototype PASS Object.getPrototypeOf(new Error) is Error.prototype PASS Object.getPrototypeOf(new Number) is Number.prototype PASS Object.getPrototypeOf(new Object) is Object.prototype PASS Object.getPrototypeOf(new String) is String.prototype PASS Object.getPrototypeOf(Array.prototype) is Object.prototype PASS Object.getPrototypeOf(Date.prototype) is Object.prototype PASS Object.getPrototypeOf(Number.prototype) is Object.prototype PASS Object.getPrototypeOf(Object.prototype) is null PASS Object.getPrototypeOf(String.prototype) is Object.prototype PASS Object.getPrototypeOf(Array) is Object.__proto__ PASS Object.getPrototypeOf(Date) is Object.__proto__ PASS Object.getPrototypeOf(Number) is Object.__proto__ PASS Object.getPrototypeOf(String) is Object.__proto__ PASS String.prototype.isPrototypeOf('') is false PASS Number.prototype.isPrototypeOf(0) is false PASS Boolean.prototype.isPrototypeOf(true) is false PASS Symbol.prototype.isPrototypeOf(Symbol()) is false PASS Array.prototype.isPrototypeOf([]) is true PASS Object.prototype.isPrototypeOf({}) is true PASS Date.prototype.isPrototypeOf(new Date) is true PASS Error.prototype.isPrototypeOf(new Error) is true PASS Number.prototype.isPrototypeOf(new Number) is true PASS Object.prototype.isPrototypeOf(new Object) is true PASS String.prototype.isPrototypeOf(new String) is true PASS Object.prototype.isPrototypeOf(Array.prototype) is true PASS Object.prototype.isPrototypeOf(Date.prototype) is true PASS Object.prototype.isPrototypeOf(Number.prototype) is true PASS Object.prototype.isPrototypeOf(String.prototype) is true PASS Object.__proto__.isPrototypeOf(Array) is true PASS Object.__proto__.isPrototypeOf(Date) is true PASS Object.__proto__.isPrototypeOf(Number) is true PASS Object.__proto__.isPrototypeOf(String) is true PASS var wasSet = false; var o = { }; o.__defineGetter__("__proto__", function() { wasSet = true }); o.__proto__; wasSet; is true PASS var wasSet = false; var o = { }; o.__defineSetter__("__proto__", function() { wasSet = true }); o.__proto__ = {}; wasSet; is true PASS var wasSet = false; var o = { }; Object.defineProperty(o, "__proto__", { "get": function() { wasSet = true } }); o.__proto__; wasSet; is true PASS var wasSet = false; var o = { }; Object.defineProperty(o, "__proto__", { "__proto__": function(x) { wasSet = true } }); o.__proto__ = {}; wasSet; is false PASS var o = {}; o.__proto__ = { x:true }; o.x is true PASS var o = {}; o.__proto__ = { x:true }; o.hasOwnProperty('__proto__') is false PASS var o = {}; o.__proto__ = { x:true }; o.x is undefined. PASS var o = {}; o.__proto__ = { x:true }; o.hasOwnProperty('__proto__') is true PASS successfullyParsed is true TEST COMPLETE