Javascript Absolute Beginners Guide, 3rd edition

Table of contentsIntroduction...................1 Parlez-Vous JavaScript? 2 Contacting Me/Getting Help...................... 21 Hello, World!... 5 What Is JavaScript?....... 7 Hello, World!.................. 9 Statements, Expressions, and Functions..12 I The Basic Stuff2 Values and Variables..................... 15 Using Variables............16 More Variable Stuff......183 Functions....... 23 What Is a Function?.....26 A Simple Function.......26 Creating a Function That Takes Arguments...........................30 Creating a Function That Returns Data...354 Conditional Statements: if, else, and switch............... 39 The If/Else Statement..40 Switch Statements.......49 Deciding Which to Use..............................555 Looping with for, while, and do…while!...................... 57 The for Loop................59 The Starting Point........62 Some for Loop Examples..........................64 The Other Loops.........676 Commenting Your Code…FTW!.... 71 What Are Comments?.72 Commenting Best Practices......................767 Timers............ 79 Delaying with setTimeout..........................808 Variable Scope.............................. 85 Global Scope...............86 Local Scope..................88 Miscellaneous Scoping Shenanigans.......899 Closures......... 95 Functions Within Functions.......................96 When the Inner Functions Aren't Self-Contained................10010 Where Should Your Code Live?.. 109 Approach #1: All the Code Lives in Your HTML Document...................113 Approach #2: The Code Lives in a Separate File................114 So, Which Approach to Use?..................11811 Console Logging Basics.............. 123 Meet the Console......124 Displaying the Console............................126 If You Want to Follow Along...................127 Console Logging 101..............................128 II It's an Object-Oriented World12 Of Pizza, Types, Primitives, and Objects................... 135 Let's First Talk About Pizza.......................136 From Pizza to JavaScript!.........................139 What Are Objects?....141 The Predefined Objects Roaming Around in JavaScript....14213 Arrays.......... 145 Creating an Array......146 Accessing Array Values............................147 Adding Items.............149 Removing Items.........151 Finding Items.............152 Merging Arrays..........152 Mapping, Filtering, and Reducing Arrays.............................153 The Old School Way.153 Modifying Each Array Item with map.....154 Getting One Value from an Array of Items...........................157 A Short Foray into Functional Programming........................16014 Strings......... 161 The Basics...................162 String Properties and Methods...............16315 Combining Strings and Variables 173 Our Setup...................17416 When Primitives Behave Like Objects....................... 179 Strings Aren't the Only Problem.............180 Let's Pick on Strings Anyway...................180 Why This Matters.......18217 Numbers...... 185 Using a Number........186 Operators...................187 Incrementing and Decrementing............188 Hexadecimal and Octal Values...............190 Special Values—Infinity and NaN...........190 The Math Object.......191 Random Numbers.....19618 Getters and Setters.................... 201 A Tale of Two Properties..........................202 Meet Getters and Setters........................20519 A Deeper Look at Objects.......... 211 Meet the Object........212 Creating Custom Objects........................222 The this Keyword.......22620 Using Classes.............................. 231 The Class Syntax and Object Creation..232 Extending Objects.....24021 Extending Built-in Objects.......... 247 Say Hello to prototype Again, Sort Of!..249 Using a Subclassing Approach................253 Extending Built-in Objects Is Controversial................25522 Arrow Functions......................... 259 What Are Arrow Functions?.....................260 Putting It All Together..............................26323 Making Sense of this and More.. 265 The this Keyword 101..............................26624 Booleans and the Stricter === and !== Operators... 277 The Boolean Object..278 The Boolean Function..............................278 Strict Equality and Inequality Operators28125 Null and Undefined.................... 283 Null..............................284 Undefined...................28426 All About JSON (JavaScript Object Notation).......... 287 What Is JSON?...........288 Looking Inside a JSON Object...............292 Reading JSON Data..297 Writing JSON Data?..300 III Working with the DOM27 JS, the Browser, and the DOM... 303 What HTML, CSS, and JavaScript Do....304 HTML Defines the Structure....................304 Prettify My World, CSS!...........................306 It's JavaScript Time!...307 Meet the Document Object Model........30928 Finding Elements in the DOM.... 315 Meet the querySelector Family...............316 It Really Is the CSS Selector Syntax........31829 Modifying DOM Elements.......... 321 DOM Elements Are Objects, Sort Of!....322 Let's Actually Modify DOM Elements.....32430 Styling Our Content................... 337 Why Would We Set Styles Using JavaScript?..............338 A Tale of Two Styling Approaches..........33831 Using CSS Custom Properties.... 345 What Are CSS Custom Properties/Variables?................346 Setting Complex Values Easily................34832 Traversing the DOM................... 353 Finding Your Way Around........................354 Putting It All Together..............................35833 Creating and Removing DOM Elements.................... 363 Creating Elements.....364 Removing Elements..372 Cloning Elements......37434 Quickly Adding Many Elements into the DOM......... 381 General Approach.....383 Getting Started..........38435 In-Browser Developer Tools........ 397 Meet the Developer Tools.......................398 IV Dealing with Events36 Events.......... 417 What Are Events?......418 Events and JavaScript..............................420 A Simple Example.....423 The Event Arguments and the Event Type.............42637 Event Bubbling and Capturing... 429 Event Goes Down, Event Goes Up........430 Meet the Phases........434 Who Cares?................437 Event, Interrupted.....43838 Mouse Events............................. 443 Meet the Mouse Events...........................444 The MouseEvent Properties....................451 Dealing with the Mouse Wheel..............45439 Keyboard Events........................ 457 Meet the Keyboard Events......................458 Using These Events...459 The Keyboard Event Properties..............460 Some Examples.........46140 Page Load Events and Other Stuff............................ 467 The Things That Happen During Page Load..........468 The DOMContentLoaded and load Events................471 Scripts and Their Location in the DOM.473 Script Elements: async and defer...........47741 Loading Script Files Dynamically 481 The Basic Technique.482 Running Our Dynamically Loaded Script First............486 Running Dependent Code After Our Script File Has Loaded........48842 Handling Events for Multiple Elements..................... 491 How to Do All This....493 V Totally Useful Topics that Only Make Sense Now43 Using Emojis in HTML, CSS, and JavaScript.............. 501 What Are Emojis Exactly?........................502 Emojis in HTML..........50344 Making HTTP/Web Requests in JavaScript................ 511 The Example..............513 Meet Fetch.................514 Meet XMLHttpRequest............................52045 Accessing the Webcam............... 529 The Example..............530 Overview of How This Works..................531 Adding the Code.......532 Examining the Code.53546 Array and Object Destructuring. 539 Destructuring Examples...........................54147 Storing Data Using Web Storage.............................. 549 How Web Storage Works........................550 Getting Your Code On.............................55248 Variable and Function Hoisting.. 559 JavaScript and Compiler Behavior.........56049 Working with Sets...................... 565 Creating a Set, Part I.566 Adding Items to a Set..............................567 How Checking for Duplicates Works......567 Creating a Set, Part 2569 Checking the Size of Our Set..................570 Deleting Items from a Set.......................571 Checking If an Item Exists.......................572 Looping Through Items in a Set.............572 Entries, Keys, and Values.........................57350 Conclusion... 577Glossary............................ 5819780137959167, TOC, 10/13/2022