JavaScript Core Reference - Beginning JavaScript - page 676

object
Object is the primitive type for JavaScript objects, from which all other objects are
descended (that is, all other objects inherit the methods and properties of the Object object).
Introduced in JavaScript 1.0, you can create an Object object using the Object constructor as
follows:

var obj = new Object();

You can also create an object using object literal notation like this:

var obj = {};

Literal notation is the preferred method of creating an object.

Properties

property introduced description

JavaScript 1.1 Used to reference the constructor function for the

object.

constructor

JavaScript 1.1 Returns the prototype for the object, which can be used to

extend the object's interface.

prototype

Methods

Method introduced description

JavaScript 1.5 Checks whether the specified

property is inherited. Returns
true if not inherited; false if
inherited.

hasOwnProperty(propertyName)

JavaScript 1.5 Determines if the specified

object is the prototype of
another object.

isPrototypeOf(obj)

JavaScript 1.5 Determines if the specified

property can be seen by a
for in loop.

propertyIsEnumerable(propertyName)

JavaScript 1.0 Converts the Object object

into a string.

toString()

JavaScript 1.1 Returns the primitive value of

the Object object.

valueOf()