Book Image

JavaScript from Beginner to Professional

By : Laurence Lars Svekis, Maaike van Putten, Codestars By Rob Percival
4 (5)
Book Image

JavaScript from Beginner to Professional

4 (5)
By: Laurence Lars Svekis, Maaike van Putten, Codestars By Rob Percival

Overview of this book

This book demonstrates the capabilities of JavaScript for web application development by combining theoretical learning with code exercises and fun projects that you can challenge yourself with. The guiding principle of the book is to show how straightforward JavaScript techniques can be used to make web apps ranging from dynamic websites to simple browser-based games. JavaScript from Beginner to Professional focuses on key programming concepts and Document Object Model manipulations that are used to solve common problems in professional web applications. These include data validation, manipulating the appearance of web pages, working with asynchronous and concurrent code. The book uses project-based learning to provide context for the theoretical components in a series of code examples that can be used as modules of an application, such as input validators, games, and simple animations. This will be supplemented with a brief crash course on HTML and CSS to illustrate how JavaScript components fit into a complete web application. As you learn the concepts, you can try them in your own editor or browser console to get a solid understanding of how they work and what they do. By the end of this JavaScript book, you will feel confident writing core JavaScript code and be equipped to progress to more advanced libraries, frameworks, and environments such as React, Angular, and Node.js.
Table of Contents (19 chapters)
16
Other Books You May Enjoy
17
Index

Accessing elements in the DOM

There are multiple methods to select elements from the DOM. After getting the elements, we are able to modify them. In the following sections, we will discuss how to get elements by their ID, tag name, and class name, and by CSS selector.

Instead of traversing it step by step as we just did, we are going to use built-in methods that can go through the DOM and return the elements that match the specifications.

We are going to use the following HTML snippet as an example:

<!DOCTYPE html>
<html>
  <body>
    <h1>Just an example</h1>
    <div id="one" class="example">Hi!</div>
    <div id="two" class="example">Hi!</div>
    <div id="three" class="something">Hi!</div>
  </body>
</html>

Let's start by accessing elements by ID.

Accessing elements by ID

We can grab elements by ID with the getElementById...