Book excerpt: Performance simply matters. Technology may allow us to "go bigger", but maybe not necessarily be better when it comes to performance. Now is the time to utilize the amazing tools that are available for making websites faster, and to learn how to improve user experience and satisfaction. This is a practical collection of tutorials on front-end website performance for web developers. It's packed with useful, real world hints and tips that you can use on your sites today. It contains: Which Browsers Should Your Website Support? by Craig Buckler Are Your WordPress Themes Flexible or Fast? by Maria Antonietta Perna Five Techniques to Lazy Load Images for Website Performance by Maria Antonietta Perna Optimizing CSS: ID Selectors and Other Myths by Ivan Curic Optimizing CSS: Tweaking Animation Performance with DevTools by Maria Antonietta Perna Lightning Fast Websites with Prefetching by Maria Antonietta Perna Optimizing Web Fonts for Performance: the State of the Art by Maria Antonietta Perna JavaScript Performance Optimization Tips: An Overview by Ivan Curic 7 Performance Tips for Jank-free JavaScript Animations by Maria Antonietta Perna What Is a CDN and How Does It Work? by Bruno Skvorc This book is for all front-end developers that want to build sites and apps that run faster. You'll need to be familiar with HTML and CSS and have a reasonable level of understanding of JavaScript in order to follow the discussion.