Primitive Data Types, Arrays, Loops, and Conditions | Object-Oriented JavaScript

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Object-Oriented JavaScript

4.5 (48)

Object-Oriented JavaScript

4.5 (48)

Overview of this book

Object-Oriented JavaScript

Object-Oriented JavaScript

Credits

Credits

About the Author

About the Author

About the Reviewers

About the Reviewers

Preface

Preface

Free Chapter

Introduction

Introduction

A Bit of History

The Winds of Change

The Present

The Future

Object-Oriented Programming

OOP Summary

Setting up Your Training Environment

Using the Firebug Console

Summary

Primitive Data Types, Arrays, Loops, and Conditions

Primitive Data Types, Arrays, Loops, and Conditions

Variables

Operators

Primitive Data Types

Primitive Data Types Recap

Arrays

Conditions and Loops

Comments

Summary

Exercises

Functions

Functions

What is a Function?

Pre-defined Functions

Scope of Variables

Functions are Data

Closures

Summary

Exercises

Objects

Objects

From Arrays to Objects

Built-in Objects

Summary

Exercises

Prototype

Prototype

The prototype Property

Augmenting Built-in Objects

Summary

Exercises

Inheritance

Inheritance

Prototype Chaining

Inheriting the Prototype Only

Uber—Access to the Parent from a Child Object

Isolating the Inheritance Part into a Function

Copying Properties

Heads-up When Copying by Reference

Objects Inherit from Objects

Deep Copy

object()

Using a Mix of Prototypal Inheritance and Copying Properties

Multiple Inheritance

Parasitic Inheritance

Borrowing a Constructor

Summary

Case Study: Drawing Shapes

Exercises

The Browser Environment

The Browser Environment

Including JavaScript in an HTML Page

BOM and DOM—An Overview

BOM

DOM

Events

XMLHttpRequest

Summary

Exercises

Coding and Design Patterns

Coding and Design Patterns

Coding Patterns

Design Patterns

Summary

Reserved Words

Reserved Words

Keywords

Future Reserved Words

Built-in Functions

Built-in Functions

Built-in Objects

Built-in Objects

Object

Array

Function

Boolean

Number

String

Date

Math

RegExp

Error Objects

Regular Expressions

Regular Expressions

Index

Index

Primitive Data Types

Any value that you use is of a certain type. In JavaScript, there are the following primitive data types:

Number—this includes floating point numbers as well as integers, for example 1, 100, 3.14.
String—any number of characters, for example "a", "one", "one 2 three".
Boolean—can be either true or false.
Undefined—when you try to access a variable that doesn't exist, you get the special value undefined. The same will happen when you have declared a variable, but not given it a value yet. JavaScript will initialize it behind the scenes, with the value undefined.
Null—this is another special data type that can have only one value, the null value. It means no value, an empty value, nothing. The difference with undefined is that if a variable has a value null, it is still defined, it only happens that its value is nothing. You'll see some examples shortly.

Any value that doesn't belong to one of the five primitive types listed above is an object. Even null is considered an...

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Programming languages

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