JavaScript Absolute Beginner's Guide

by Kirupa Chinnathambi

Overview

Who knew how simple using JavaScript could be?

Make the most of JavaScript—even if you've never programmed anything before. JavaScript Absolute Beginner's Guide is the fastest way to learn JavaScript and use it together with CSS3 and HTML5 to create powerful web and mobile experiences. Learn how to do what you want, the way you want, one incredibly easy step at a time. JavaScript has never been this simple!

Here's a small sample of what you'll learn:

• Organize your code with variables
• Understand how functions make your code reusable
• Use the popular if/else statement to help make a decision in code
• Learn about switch statements and when to use them
• Work with for, while, and do...while loops
• Learn how to use global and local scope
• Understand what closures are
• Learn about the various places your code can live
• Understand how to write comments and use good commenting practices
• Learn about the basic types of objects you'll run into in JavaScript
• Find out that pizza has an educational value beyond just being deliciously awesome
• Learn how to perform common string operations
• Use arrays to handle lists of data
• Learn to create custom objects
• Get up to speed on some of the big ES6 changes

Product Details

ISBN-13:	9780136502890
Publisher:	Pearson Education
Publication date:	12/27/2019
Series:	Absolute Beginner's Guide
Edition description:	2nd ed.
Pages:	464
Sales rank:	1,072,677
Product dimensions:	6.90(w) x 9.00(h) x 1.00(d)

About the Author

Kirupa Chinnathambi has spent most of his life trying to teach others to love web development as much as he does. In 1999, before blogging was even a word, he started posting tutorials on kirupa.com. Since then, he has written hundreds of articles, authored books, and recorded many YouTube training videos.

Table of Contents

Introduction 1


Parlez-vous JavaScript? 2


Contacting Me/Getting Help 3


Chapter 1 Hello, World! 5


What Is JavaScript? 7


Hello, World! 8


The HTML Document 8


Looking at the Code: Statements and Functions 11


PART I: THE BASIC STUFF


Chapter 2 Values and Variables 15


Using Variables 16


More Variable Stuff 17


Naming Variables 17


More on Declaring and Initializing Variables 18


Chapter 3 Functions 21


What Is a Function? 23


A Simple Function 24


Creating a Function that Takes Arguments 28


Creating a Function that Returns Data 33


The Return Keyword 33


Exiting the Function Early 34


Chapter 4 Conditional Statements: If, Else, and Switch 37


The If / Else Statement 39


Meet the Conditional Operators 41


Creating More Complex Expressions 44


Variations on the If / Else Statement 45


Phew 47


Switch Statements 47


Using a Switch Statement 47


Similarity to an If/Else Statement 51


Deciding Which to Use 53


Chapter 5 Looping with For, While, and Do…While! 55


The for Loop 57


The Starting Point 61


The Step 61


The Condition (aka How Long to Keep Looping) 62


Putting It All Together 62


Some for Loop Examples 63


Breaking a Loop 63


Skipping an Iteration 64


Going Backwards 64


You Don't Have to Use Numbers 65


Oh, No He Didn't! 65


The Other Loops 66


The while Loop 66


The do…while Loop 66


Chapter 6 Commenting Your CodeFTW! 69


What Are Comments? 70


Single Line Comments 71


Multi-Line Comments 72


Commenting Best Practices 73


Chapter 7 Timers 77


Delaying with setTimeout 78


Looping with setInterval 79


Animating Smoothly with requestAnimationFrame 80


Chapter 8 Variable Scope 83


Global Scope 84


Local Scope 86


Miscellaneous Scoping Shenanigans 87


Block Scoping 87


How JavaScript Processes Variables 90


Closures 92


Chapter 9 Closures 93


Functions within Functions 94


When the Inner Functions Aren't Self-Contained 98


Chapter 10 Where Should Your Code Live? 105


Approach #1: All the Code Lives in Your HTML Document 109


Approach #2: The Code Lives in a Separate File 110


The JavaScript File 110


Referencing the JavaScript File 111


So…Which Approach to Use? 114


Yes, My Code Will Be Used on Multiple Documents! 114


No, My Code Is Used Only Once on a Single HTML Document! 116


PART II: IT'S AN OBJECT-ORIENTED WORLD


Chapter 11 Console Logging Basics 119


Meet the Console 120


Displaying the Console 121


If You Want to Follow Along 124


Console Logging 101 125


Meet the Log Method 125


Going Beyond Predefined Text 127


Displaying Warnings and Errors 128


Chapter 12 Of Pizza, Types, Primitives, and Objects 133


Let's First Talk About Pizza 134


From Pizza to JavaScript! 136


What Are Objects? 138


The Predefined Objects Roaming Around in JavaScript 140


Chapter 13 Arrays 143


Creating an Array 144


Accessing Array Values 145


Adding Items to Your Array 147


Removing Items from the Array 149


Finding Items in the Array 150


Merging Arrays 150


Mapping, Filtering, and Reducing Arrays 151


The Old School Way 151


Modifying Each Array Item with Map 152


Filtering Items 154


Getting One Value from an Array of Items 155


A Short Foray into Functional Programming 157


Chapter 14 Strings 159


The Basics 160


String Properties and Methods 161


Accessing Individual Characters 161


Combining (aka Concatenating) Strings 163


Getting Substrings out of Strings 164


Splitting a String/split 165


Finding Something Inside a String 166


Upper and Lower Casing Strings 168


Chapter 15 When Primitives Behave Like Objects 169


Strings Aren't the Only Problem 170


Let's Pick on Strings Anyway 170


Why This Matters 172


Chapter 16 Numbers 175


Using a Number176


Operators 176


Doing Simple Math 177


Incrementing and Decrementing 177


Hexadecimal and Octal Values 179


Special Values—Infinity and NaN 180


Infinity 180


NaN 180


The Math Object 180


The Constants 181


Rounding Numbers 182


Trigonometric Functions 183


Powers and Square Roots 184


Getting the Absolute Value 185


Random Numbers 185


Chapter 17 Getters and Setters 187


A Tale of Two Properties 188


Meet Getters and Setters 190


Shout Generator 191


Logging Activity 191


Property Value Validation 192


Chapter 18 A Deeper Look at Objects 195


Meet the Object 196


Creating Objects 197


Adding Properties 197


Removing Properties 200


What Is Going on Behind the Scenes? 201


Creating Custom Objects 205


The this Keyword 209


Chapter 19 Extending Built-in Objects 213


Say Hello to prototype…again—Sort of! 214


Extending Built-in Objects is Controversial 219


You Don't Control the Built-in Object's Future 219


Some Functionality Should Not Be Extended or Overridden 219


Chapter 20 Using Classes 221


The Class Syntax and Object Creation 222


Creating an Object 222


Meet the Constructor 224


What Goes Inside the Class 226


Extending Objects 229


Chapter 21 Booleans and the Stricter === and !== Operators 237


The Boolean Object 238


The Boolean Function 238


Strict Equality and Inequality Operators 240


Chapter 22 Null and Undefined 243


Null 244


Undefined 244


PART III: Working with the DOM


Chapter 23 All About JSON (aka JavaScript Object Notation) 247


What Is JSON? 248


Looking Inside a JSON Object 252


Property Names 252


The Values 253


Reading JSON Data 257


Parsing JSON-looking Data into Actual JSON 259


Writing JSON Data? 259


Chapter 24 JS, the Browser, and the Dom 261


What HTML, CSS, and JavaScript Do 262


HTML Defines the Structure 262


Prettify My World, CSS! 264


It's JavaScript Time! 265


Meet the Document Object Model 267


The Window Object 269


The Document Object 269


Chapter 25 Finding Elements in the Dom 273


Meet the querySelector Family 274


querySelector 275


querySelectorAll 275


It Really Is the CSS Selector Syntax 276


Chapter 26 Modifying Dom Elements 279


DOM Elements Are Objects—Sort of! 280


Let's Actually Modify DOM Elements 282


Changing an Element's Text Value 284


Attribute Values 286


Chapter 27 Styling Our Content 289


Why Would We Set Styles Using JavaScript? 290


A Tale of Two Styling Approaches 290


Setting the Style Directly 290


Adding and Removing Classes Using JavaScript 292


Checking Whether a Class Value Exists 294


Going Further 294


Chapter 28 Traversing the Dom 297


Finding Your Way Around 298


Dealing with Siblings and Parents 301


Let's Have Some Kids! 301


Putting It All Together 302


Checking If A Child Exists 303


Accessing All the Child Elements 303


Walking the DOM 303


Chapter 29 Creating and Removing Dom Elements 305


Creating Elements 306


Removing Elements 314


Cloning Elements 315


Chapter 30 In-Browser Developer Tools 323


Meet the Developer Tools 324


Inspecting the DOM 326


Debugging JavaScript 331


Meet the Console 337


Inspecting Objects 338


Logging Messages 340


PART IV: DEALING WITH EVENTS


Chapter 31 Events 343


What Are Events? 344


Events and JavaScript 346


1. Listening for Events 346


2. Reacting to Events 348


A Simple Example 348


The Event Arguments and the Event Type 351


Chapter 32 Event Bubbling and Capturing 355


Event Goes Down Event Goes Up 356


Meet the Phases 361


Who Cares? 363


Event, Interrupted 364


Chapter 33 Mouse Events 367


Meet the Mouse Events 368


Clicking Once and Clicking Twice 368


Mousing Over and Mousing Out 370


The Very Click-like Mousing Down and Mousing Up Events 372


The Event Heard Again…and Again…and Again! 373


The Context Menu 374


The MouseEvent Properties 375


The Global Mouse Position 375


The Mouse Position Inside the Browser 376


Detecting Which Button Was Clicked 377


Dealing with the Mouse Wheel 378


Chapter 34 Keyboard Events 381


Meet the Keyboard Events 382


Using These Events 383


The Keyboard Event Properties 384


Some Examples 385


Checking That a Particular Key Was Pressed 385


Doing Something When the Arrow Keys Are Pressed 386


Detecting Multiple Key Presses 386


Chapter 35 Page Load Events and Other Stuff 391


The Things That Happen During Page Load 392


Stage Numero Uno 393


Stage Numero Dos 393


Stage Numero Three 394


The DOMContentLoaded and load Events 395


Scripts and Their Location in the DOM 397


Script Elements—Async and Defer 400


async 400


defer 400


Chapter 36 Handling Events for Multiple Elements 405


How to Do All of This 407


A Terrible Solution 408


A Good Solution 409


Putting It All Together 412


Chapter 37 Conclusion 415


Glossary 419


Index 423