Pro JavaScript Performance [electronic resource] : Monitoring and Visualization /
Barker, Tom.author.
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 sites smooth 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.
Title Page; Copyright Page; Contents at a Glance; Table of Contents; About the Author; About the Technical Reviewer; Acknowledgments; Chapter 1: What is Performance; Web Performance; Parsing and Rendering; Rendering Engines; JavaScript Engines; Runtime Performance; Why does performance matter?; Instrumentation and Visualization; The Goal of This Book; Technologies Used and Further Reading; Summary; Chapter 2: Tools and Technology to Measure and Impact Performance; Firebug; How to Install; How to Use; YSlow; How to Install; How to Use; WebPagetest; Minification; Minify; YUI Compressor
Closure CompilerComparison of Results; Analysis and Visualization; Getting Started with R; Installing and Running R; An R Primer; Simple Charting with R; A Practical Example of R; Using apply(); Summary; Chapter 3: WPTRunner-Automated Performance Monitoring and Visualization; Architecture; Creating a Shared Configuration File; Accessing the WebPagetest API; Parsing the Test Results; Complete Example; Charting with R; Parsing the Data; Plotting Load Time; Plotting Payload and Number of HTTP Requests; Open Source; Summary; Interview with Patrick Meenan of WebPagetest
What was the original inspiration for creating WebPagetest?Was it tough getting the project open sourced?; What were some of the challenges that you ran into while working on the project?; What is the goal of WebPagetest LLC?; How long are test results stored?; How long do tests take to run on average?; Do you recommend a different approach than polling for test complete when using the API?; What is the process for tests going through your queue?; What are some of the most interesting things you have heard that people are doing with WebPagetest?
Could you talk a little bit about the agent architecture?How do you use WebPagetest with the applications that you develop?; What features are in the near and longer term for WebPagetest? Personally I'd love a memory profiler.; Chapter 4: perfLogger-JavaScript Benchmarking and Logging; Architecture; Let's Code!; Calculating Test Results; Setting Test Result Metadata; Displaying Test Results; Saving the Data; Crafting the Public API; Remote Logging; Saving the Test Results; An Example Page; Charting the Results; Open Source; Summary; Chapter 5: Looking Forward, a Standard for Performance
W3C Web Performance Working GroupThe Performance Object; Performance Timing; Integrating the Performance Object with perfLogger; Updating the Logging Functionality; Performance Navigation; Performance Memory; High-Resolution Time; Visualizing the New Data; Summary; Chapter 6: Web Performance Optimizations; Optimizing Page Render Bottlenecks; Script Loading; async; Compare Results; Lazy Loading; The Art of Lazy Loading; Lazy Loading Scripts; Lazy Loading CSS; Why Not to Lazy Load Images; Summary; Chapter 7: Runtime Performance; Cache Variables and Properties across Scope; Creating a New File
Creating Tests
Includes index.
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 sites smooth 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.
Computer programming.
Software engineering.
Web Development.
Software Engineering/Programming and Operating Systems.