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JavaScript from Beginner to Professional

You're reading from   JavaScript from Beginner to Professional Learn JavaScript quickly by building fun, interactive, and dynamic web apps, games, and pages

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Product type Paperback
Published in Dec 2021
Publisher Packt
ISBN-13 9781800562523
Length 546 pages
Edition 1st Edition
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Authors (4):
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Codestars By Rob Percival Codestars By Rob Percival
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Codestars By Rob Percival
Laurence Svekis Laurence Svekis
Author Profile Icon Laurence Svekis
Laurence Svekis
Maaike van Putten Maaike van Putten
Author Profile Icon Maaike van Putten
Maaike van Putten
Rob Percival Rob Percival
Author Profile Icon Rob Percival
Rob Percival
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Toc

Table of Contents (19) Chapters Close

Preface 1. Getting Started with JavaScript FREE CHAPTER 2. JavaScript Essentials 3. JavaScript Multiple Values 4. Logic Statements 5. Loops 6. Functions 7. Classes 8. Built-In JavaScript Methods 9. The Document Object Model 10. Dynamic Element Manipulation Using the DOM 11. Interactive Content and Event Listeners 12. Intermediate JavaScript 13. Concurrency 14. HTML5, Canvas, and JavaScript 15. Next Steps 16. Other Books You May Enjoy
17. Index
Appendix – Practice Exercise, Project, and Self-Check Quiz Answers

Basic functions

We have been calling functions for a while already. Remember prompt(), console.log(), push(), and sort() for arrays? These are all functions. Functions are a group of statements, variable declarations, loops, and so on that are bundled together. Calling a function means an entire group of statements will get executed.

First, we are going to have a look at how we can invoke functions, and then we will see how to write functions of our own.

Invoking functions

We can recognize functions by the parentheses at the end. We can invoke functions like this:

nameOfTheFunction();
functionThatTakesInput("the input", 5, true);

This is invoking a function called nameOfTheFunction with no arguments, and a function called functionThatTakesInput with three required arguments. Let's have a look at what functions can look like when we start writing them.

Writing functions

Writing a function can be done using the function keyword. Here...

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