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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

BLOB AND FILE APIs

One of the major pain points of web applications has been the inability to interact with files on a user's computer. Since before 2000, the only way to deal with files was to place <input type="file"> into a form and leave it at that. The Blob and File APIs are designed to give web developers access to files on the client computer in a secure manner that allows for better interaction with those files.

The File Type

The File API is still based around the file input field of a form but adds the ability to access the file information directly. HTML5 adds a files collection to DOM for the file input element. When one or more files are selected in the field, the files collection contains a sequence of File objects that represent each file. Each File object has several read-only properties, including:

  • name—The file name on the local system.
  • size—The size of the file in bytes.
  • type—A string containing the MIME type of the file.
  • ...
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