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Professional JavaScript for Web Developers

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

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Product type Paperback
Published in Nov 2019
Publisher Wiley
ISBN-13 9781119366447
Length 1144 pages
Edition 4th Edition
Languages
Tools
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Author (1):
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Matt Frisbie Matt Frisbie
Author Profile Icon Matt Frisbie
Matt Frisbie
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Table of Contents (37) Chapters Close

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

THE <NOSCRIPT> ELEMENT

Of particular concern to early browsers was the graceful degradation of pages when the browser didn't support JavaScript. To that end, the <noscript> element was created to provide alternate content for browsers without JavaScript. Although effectively 100% of browsers now support JavaScript, this element is still useful for browsers that explicitly disable JavaScript.

The <noscript> element can contain any HTML elements, aside from <script>, that can be included in the document <body>. Any content contained in a <noscript> element will be displayed under only the following two circumstances:

  • The browser doesn't support scripting.
  • The browser's scripting support is turned off.

If either of these conditions is met, then the content inside the <noscript> element is rendered. In all other cases, the browser does not render the content of <noscript>.

Here is a simple example:

<!DOCTYPE html>
<html...
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