Java Reference
In-Depth Information
5
JavaScript — An Object-
Based Language
In this chapter, you look at a concept that is central to JavaScript, namely
objects
. But what are
objects, and why are they useful?
First, we have to break it to you: You have been using objects throughout this topic (for example,
an array is an object). JavaScript is an object-based language, and therefore most of what you do
involves manipulating objects. You'll see that when you make full use of these objects, the range
of things you can do with JavaScript expands immensely.
We'll start this chapter by taking a look at the idea of what objects are and why they are impor-
tant. We'll move on to what kinds of objects are used in JavaScript, how to create them and
use them, and how they simplify many programming tasks for you. Finally, you'll see in more
detail some of the most useful objects that JavaScript provides and how to use these in practical
situations.
Not only does the JavaScript language consist of a number of these things called objects (which
are also called
native JavaScript objects
), but also the browser itself is modeled as a collection of
objects available for your use. You'll learn about these objects in particular in the next chapter.
Object-Based Programming
Object-based programming is a slightly scarier way of saying “programming using objects.” But
what are these objects that you will be programming with? Where are they and how and why
would you want to program with them? In this section, you'll look at the answers to these ques-
tions, both in general programming terms and more specifi cally within JavaScript.
