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:Â 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:Â 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 101Â Â Â 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:Â Working with the DOM
Chapter 23Â All About JSON (aka JavaScript Object Notation)Â Â Â 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:Â 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 DOMÂ Â Â 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
