A page in the |
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Introduction |
Basics |
Statements · Control Flow Statements · Comments · Objects · Functions · Style |
Features |
Scoping · Inheritance · DOM |
It has been suggested that this page or section be merged into Wikibooks:JavaScript. (Discuss)
An object is a great way to keep track of a bunch of related information. Additionally, the information contained in one object can be "inherited" by another. For example, imagine a program which represents cars. Other languages like PHP, Java, or C++ force the programmer to act as a manufacturer, providing a blueprint with every detail of how each vehicle's parts will work before it ever runs. But JavaScript lets you add and remove parts as needed, so you can have a Ferrari one second and a seaplane the next. And if at some point you particularly like the current arrangement, you can instantly make unlimited copies.
Syntax[]
Objects are initialized via braces {}
; they may be populated either during initialization or later. The following examples are effectively identical:
var obj = {foo: 'bar'};
var obj = {};
obj.foo = 'bar';
If a property is accessed before being initialized, its value is undefined
.