Book Image

Object-Oriented JavaScript - Second Edition

Book Image

Object-Oriented JavaScript - Second Edition

Overview of this book

JavaScript is the behavior, the third pillar in today's paradigm that looks at web pages as something that consists of clearly distinguishable parts: content (HTML), presentation (CSS) and behavior (JavaScript). Using JavaScript, you can create not only web pages but also desktop widgets, browser and application extensions, and other pieces of software. It's a pretty good deal: you learn one language and then code all kinds of different applications. While there's one chapter specifically dedicated to the web browser environment including DOM, Events and AJAX tutorials, the rest is applicable to the other environments Many web developers have tried coding or adopting some bits of JavaScript, but it is time to "man up" and learn the language properly because it is the language of the browser and is, virtually, everywhere. This book starts from zero, not assuming any prior JavaScript programming knowledge and takes you through all the in-depth and exciting futures hidden behind the facade. Once listed in the "nice to have" sections of job postings, these days the knowledge of JavaScript is a deciding factor when it comes to hiring web developers. After reading this book you'll be prepared to ace your JavaScript job interview and even impress with some bits that the interviewer maybe didn't know. You should read this book if you want to be able to take your JavaScript skills to a new level of sophistication.
Table of Contents (19 chapters)
Object-Oriented JavaScript Second Edition
About the Authors
About the Reviewer
Built-in Functions
Regular Expressions


Based on the idea that objects inherit from objects, Douglas Crockford advocates the use of an object() function that accepts an object and returns a new one that has the parent as a prototype.

function object(o) {
function F() {}
F.prototype = o;
return new F();

If you need access to an uber property, you can modify the object() function like so:

function object(o) {
var n;
function F() {}
F.prototype = o;
n = new F();
n.uber = o;
return n;

Using this function is the same as using the extendCopy(): you take an object such as twoDee, create a new object from it and then proceed to augmenting the new object.

var triangle = object(twoDee); = 'Triangle';
triangle.getArea = function () {
return this.side * this.height / 2;

The new triangle still behaves the same way:

"Shape, 2D shape, Triangle"

This pattern is also referred to as prototypal inheritance , because you use a parent object as the prototype of a child object. It's also adopted and built...