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Web Compatibility and Performance Testing in a Multi-Browser World

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This presentation was given at the 2009 AJAX Experience Conference by Gomez's CTO Imad Mouline and Director, Agent Technology.

Today’s browser diversity brings new challenges to Web designers and developers. JavaScript loads and performs differently across browsers such as Internet Explorer 7 and 8, Firefox, Safari and Chrome, and can lead to inconsistent content rendering, poor Web performance, and frustrated end-users. Traditional methods for Web performance testing and monitoring cannot find and diagnose browser-specific, client-side performance problems.

This session was designed to help developers learn how to:
• Improve content rendering across multiple browsers and operating systems
• Understand and improve object load order, browser by browser
• Ensure that third-party content doesn’t degrade client-side performance
• Realistically preview performance under load in each browser.

Publicado en: Tecnología
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Web Compatibility and Performance Testing in a Multi-Browser World

  1. 1. Web Compatibility and Performance Testing in a Multi-Browser World Imad Mouline, CTO, Gomez (@imadmouline) Buddy Brewer, Director of Engineering, Agent Technology, Gomez (@bbrewer)
  2. 2. Agenda • The problem and the upside • Functional validation across browsers • Performance optimization across browsers • Raw vs. perceived performance • Key takeaways and Q&A
  3. 3. The Problem • Building applications is more complex • Developers now support an interrelated mess of technologies that differ from browser to browser • Networking stack • JS engine • Rendering technologies (CSS, Canvas, SVG)
  4. 4. The Upside • Browsers provide better performance, richer functionality • The rate of change is accelerating, with competition between vendors leading to massive gains in performance
  5. 5. How? • We need to understand how our applications perform in real browsers on the real network • We need to know both what users encounter and what they perceive
  6. 6. Asymmetric Advantages of Modern Browsers • Dramatically faster JS engines • Greater connection parallelism • Client side storage • Native CSS selectors • 2D compositing (Canvas, SVG)
  7. 7. Testing Presentation • Bespin determines browser Canvas support at runtime • Which browsers provide adequate support?
  8. 8. Yes: Firefox 3.5, Safari 4
  9. 9. No: Firefox 2, Safari 3, Any IE
  10. 10. Maybe: Chrome
  11. 11. Functional Validation • As new versions ship, do the expected browsers still work? • As new browsers are released, do our applications still work?
  12. 12. Revisiting Performance Optimization • Are our old techniques still relevant as the browsers we target evolve? • Example: Domain sharding • Legacy browsers allow 2 connections per hostname • Domain sharding increases parallelism to boost static object performance via pointing multiple hostnames to the same host
  13. 13. Optimizing IE6 Behavior • For older browsers, this could represent an easy 50% load time savings
  14. 14. Optimizing IE6 Behavior • What’s the catch?
  15. 15. De-optimizing IE8 Behavior • In IE8 (and Firefox and Safari and Chrome) using domain sharding leads to a glut of simultaneous connection creation and a dramatic performance hit
  16. 16. Lessons • Optimization techniques must evolve along with the browsers • So, performance testing should take into account browser differences • And to do that, we need to know what browsers are visiting our site
  17. 17. ▪ Difference between quickest and slowest browser load time equals 13.226 seconds ▪ Large sample of US end-users, on broadband connections, visiting a particular page on a web site over a 48 hour period Performance Differences by Browser
  18. 18. ▪ Load time for MS Internet Explorer higher than Firefox ▪ Perceived render time for MS Internet Explorer lower than Firefox ▪ Perceived render time is the amount of time needed for the page layout to stabilize and for all content visible to the end-user above the fold to be completely rendered Load Time vs. Perceived Render Time
  19. 19. Optimizing Perceived Render Time & User Experience • Most prominent image on site loads almost last • Changing load order will not impact raw page performance, but will improve perceived render time and user experience
  20. 20. What is the download order?
  21. 21. Factors that impact object download order • Browser type / version • Host latency, concurrency differences • Geography • Geography???
  22. 22. San Jose
  23. 23. Boston
  24. 24. Page Load TimeCache Level Browser Cache Impact
  25. 25. Takeaways – Summary • Know your end-users • Identify where and how they use your application, how they connect to the network, when they do it, where they do it from, what browser they use, etc… • Deliver on their expectations • Know your entire application • Build performance into your process • Improve raw, workflow, and perceived performance • Continuously evaluate your performance targets • Measure what matters • Measure from your end-users’ perspective • Align your end-users’ web experience with your requirements and ultimate business goals
  26. 26. Please complete an evaluation.
  27. 27. Questions?