This test checks whether various seal/freeze/preventExtentions work on a regular object. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS (new inextensible).prototypeExists is true PASS (new sealed).prototypeExists is true PASS (new frozen).prototypeExists is true PASS test(obj()) is "(b:4)(c:3)E" PASS test(preventExtensions(obj())) is "(b:4)" PASS test(seal(obj())) is "(a:1)(b:4)S" PASS test(freeze(obj())) is "(a:1)(b:2)SF" PASS Object.preventExtensions(Math.sin) is Math.sin PASS var o = {}; Object.preventExtensions(o); o.__proto__ = { newProp: "Should not see this" }; o.newProp; threw exception TypeError: Attempted to assign to readonly property.. PASS "use strict"; var o = {}; Object.preventExtensions(o); o.__proto__ = { newProp: "Should not see this" }; o.newProp; threw exception TypeError: Attempted to assign to readonly property.. PASS Object.preventExtensions(Math); Math.sqrt(4) is 2 PASS var arr = Object.preventExtensions([]); arr[0] = 42; arr[0] is undefined. PASS var arr = Object.preventExtensions([]); arr[0] = 42; arr.length is 0 PASS "use strict"; var arr = Object.preventExtensions([]); arr[0] = 42; arr[0] threw exception TypeError: Attempted to assign to readonly property.. PASS obj.foo is 1 PASS Object.isFrozen(func) is true PASS func.prototype === 42 is false PASS Object.getOwnPropertyDescriptor(func, "prototype").writable is false PASS Object.isFrozen(strictFunc) is true PASS strictFunc.prototype === 42 is false PASS Object.getOwnPropertyDescriptor(strictFunc, "prototype").writable is false PASS Object.isFrozen(array) is true PASS array[0] is 0 PASS Object.getOwnPropertyDescriptor(array, "length").writable is false PASS Object.isFrozen(args) is true PASS args[0] is 0 PASS Object.getOwnPropertyDescriptor(args, "length").writable is false PASS Object.getOwnPropertyDescriptor(args, "callee").writable is false PASS preventExtensionsFreezeIsFrozen(function foo(){}) is true PASS preventExtensionsFreezeIsFrozen(function foo(){ "use strict"; }) is true PASS preventExtensionsFreezeIsFrozen([0,1,2]) is true PASS preventExtensionsFreezeIsFrozen((function(){ return arguments; })(0,1,2)) is true PASS Object.getOwnPropertyDescriptor(freeze({0:0}), 0).configurable is false PASS Object.getOwnPropertyDescriptor(freeze({10000001:0}), 10000001).configurable is false PASS successfullyParsed is true TEST COMPLETE