You're reading from Professional JavaScript for Web Developers Discover an easy-to-learn guide to upgrade your JavaScript skills

Product type Paperback

Published in Nov 2019

Publisher Wiley

ISBN-13 9781119366447

Length 1144 pages

Edition 4th Edition

Languages

JavaScript

Tools

Combine

Concepts

Web Programming

Author (1):

Matt Frisbie

View More author details

Table of Contents (37) Chapters

COVER FREE CHAPTER

FOREWORD

INTRODUCTION

1 What Is JavaScript?

2 JavaScript in HTML

3 Language Basics

4 Variables, Scope, and Memory

5 Basic Reference Types

6 Collection Reference Types

7 Iterators and Generators

8 Objects, Classes, and Object-Oriented Programming

9 Proxies and Reflect

10 Functions

11 Promises and Async Functions

12 The Browser Object Model

13 Client Detection

14 The Document Object Model

15 DOM Extensions

16 DOM Levels 2 and 3

17 Events

18 Animation and Graphics with Canvas

19 Scripting Forms

20 JavaScript APIs

21 Error Handling and Debugging

22 XML in JavaScript

23 JSON

24 Network Requests and Remote Resources

25 Client-Side Storage

26 Modules

27 Workers

28 Best Practices

A ES2018 and ES2019

B Strict Mode

C JavaScript Libraries and Frameworks

D JavaScript Tools

INDEX

END USER LICENSE AGREEMENT

PERFORMANCE

The amount of JavaScript that developers now write per web page has grown dramatically since the language was first introduced. With that increase came concerns over the runtime execution of JavaScript code. JavaScript was originally an interpreted language, so the speed of execution was significantly slower than it was for compiled languages. Chrome was the first browser to introduce an optimizing engine that compiles JavaScript into native code. Since then, all other major browsers have followed suit and have implemented JavaScript compilation.

Even with the move to compiled JavaScript, it's still possible to write slow code. However, there are some basic patterns that, when followed, ensure the fastest possible execution of code.

Be Scope-Aware

The “Variables, Scope, and Memory” chapter discussed the concept of scopes in JavaScript and how the scope chain works. As the number of scopes in the scope chain increases, so does the amount of time it takes...