Performance is a hugely important area of web development. If your site runs slowly, users are going to leave, and the problem only grows as your site gets more popular. Pro JavaScript Performance gives you the tools you need to keep your sitessmooth and responsive no matter how many users you have. Best practices are changing or becoming redefined continually because of changes and optimizations at the interpreter level, and differences in system configuration, and network speeds. This is exacerbated by the quickened release schedule that most browsers have adopted. Just as important as following best practices is the ability to measure your own performance, so that you can adjust as times change, and so that you can note the subtle nuances in your own code and define your own best practices by your own observations. This book gives you the tools to observe and track the performance of your web applications over time from multiple perspectives, so that you are always aware of, and can fix,all aspects of your performance. What youll learn Describes the different aspects of performance, and explores the tools for quantifying and improving performance Provides tactical solutions for creating tools to measure the performance of your own web applications Learn to apply performance best practices, and how to quantify your results Who this book is for Pro JavaScript Performance is written for advanced JavaScript users and web developers. You will need a strong understanding of JavaScript to get the most from this book. Table of Contents What Is Performance? Tools and Technology to Measure and Impact Performance WPTRunnerAutomated Performance Monitoring and Visualization with WebPagetest perfLoggerJavaScript Benchmarking and Logging Looking Forward, A Standard for Performance Web Performance Optimizations Runtime Performance Balancing Performance with Software Engineering Best Practices and Running in Production