Understanding the DOM

JavaScript is the de facto programming language of the web, but the language itself does not include any built-in method for working with input/output (I/O), such as graphics display and sound. Instead, the web browser provides an API for accessing the HTML document in a tree structure known as the Document Object Model (DOM). The combination of JavaScript and the DOM is what allows us to create interactive, dynamic websites.

Many modern frameworks, such as React, Vue, and Svelte abstract away much of the DOM from the developer, but frameworks also use the DOM under the hood. The JavaScript library jQuery was also created to make working with the DOM easier, but the modern development practice is to work with the DOM directly. In order to be a proficient web developer, having a deep understanding of what the DOM is and how to work with it is essential. The goal of this book is to provide a base understanding of the DOM, as well as explore examples of the most common and useful methods for interacting with the DOM.

The topics that it covers include:
- The DOM and DOM tree structure;
- How to access, traverse, and modify nodes and elements in the DOM;
- How to modify attributes, classes, and styles in the DOM;
- Use events to make interactive, dynamic websites.

Each chapter is self-contained and can be followed independently of the others. However, if you are not yet familiar with the concept of the DOM and DOM tree, it is recommended that you read the introductory chapters first.