You Don't Need JavaScript

A CSS-first guide to replace unnecessary JavaScript with modern HTML and CSS. Learn to build modals, dark mode, smooth scrolling, form validation, popovers, and more with modern HTML and CSS.

Key Features

• Build common UI patterns with modern HTML and CSS instead of unnecessary JavaScript
• Learn solid production techniques and latest platform features you can adopt with progressive enhancement
• Explore real interface problems about accessibility, performance, and maintainability with real-world examples

Book Description

For years, JavaScript has been the default answer for almost every interactive detail on the web. Need a modal, a dropdown, dark mode, smooth scrolling, or form validation? Most frontend developers reach for JavaScript without thinking twice. But the platform has changed.

This book shows how much modern HTML and CSS can already do on their own. Through practical examples, you will learn how to build real interface patterns with less code, fewer dependencies, and a stronger focus on accessibility, performance, and maintainability.

You will explore features such as :has(), native dialogs, accordions, sliders, counters, dark mode, smooth scrolling, form validation, border animations, view transitions, motion paths, and mask effects. The book also introduces newer browser features like popovers, anchor positioning, scroll-driven animations, customizable selects, and CSS carousels.

The goal is not to avoid JavaScript at all costs. It is to use it when it actually adds value, and not by default. By the end of the book, you will have a clearer sense of what the platform can handle today and how to build interfaces that are lighter, cleaner, and more resilient.

What you will learn

• Apply the Rule of Least Power in real UI decisions
• Choose modern HTML and CSS over JS where it's sufficient
• Build lightweight, accessible interfaces in practice
• Use modern CSS features like :has(), view transitions, motion paths, masks, popovers, and anchor positioning
• Create UI patterns like dark mode, dialogs, accordions, smooth scrolling, custom selects, and carousels
• Implement progressive enhancement in real projects
• Improve performance by reducing unnecessary JS

Who this book is for

This book is for people who build interfaces and want to rely less on JavaScript when they do not have to. It is aimed at front-end developers, designers who code, and curious CSS people who already know the basics and want to see how far modern HTML and CSS can really go. If you have ever added JavaScript out of habit for something the browser can already handle, this book will give you a different way to think about that.

Table of Contents

1. Conditionally Styling with :has()
2. Dark Mode in CSS
3. Smooth Scrolling to Sections
4. Native Modals with
5. Accordions with Pure CSS
6. Pure-CSS Automatic Slider
7. Auto‑Numbered Headings
8. Other Use-Case of Counter
9. Custom Border Animations
10. View Transitions
11. CSS Motion Path
12. CSS Mask Effects
13. CSS-Only Form Validation
14. Scroll-Driven Animations
15. Native Popovers
16. Customized Selects
17. Anchor Positioning
18. Native CSS Carousels
19. And more to come...  
20. Closing Thoughts

Theo Soti is a frontend developer, writer, and educator focused on modern CSS, semantic HTML, and building lighter web experiences. Through practical experiments and real interface patterns, he helps developers question JavaScript-first habits and make better use of the platform. His work centers on accessibility, performance, and progressive enhancement, with a clear goal: helping teams build websites that are faster, and more resilient.