Why is Web Performance Optimization Important and what are some things developers can do to ensure their applications perform well and please end users?

1. StirTrek Edition
10 Things You Can Do
Today To Speed Up Your
Web Application & Make
More $$$$ Today!
Chris Love
@ChrisLove
Love2Dev.com

2. Who Am I
• ASP.NET MVP
• ASP Insider
• Internet Explorer User Agent
• Author
• Speaker
• Tweaker, Lover of Web, JavaScript, CSS & HTML5
• @ChrisLove
• Love2Dev.com

3. High Performance Single Page Web
Applications
• Responsive Design
• Touch
• Mobile First
• SPA
• Extensible, Scalable Architecture
• Web Build and Workflow
• Goes Really Fast!
• ~395 Pages
• 20 Chapters
• $9.99 http://amzn.to/1a55L89

4. Slide Deck & Source Code
• Slide Deck – slidesha.re/15YTrTT
• Source Code – http://GitHub.com/docluv

6. Annoying?

8. Web Performance Optimization
Web performance optimization, WPO, or website optimization involves
ongoing monitoring and testing of websites to achieve optimum
performance under given constraints. Usually optimization is restricted
due to lack of complete information and metrics to evaluate the
performance of a website.
http://bit.ly/SWEh6E

9. Matt Cutts
"Also take a step back for a minute and consider the intent of this
change: a faster web is great for everyone, but especially for users.
Lots of websites have demonstrated that speeding up the user
experience results in more usage. So speeding up your website isn’t
just something that can affect your search rankings–it’s a fantastic idea
for your users.“
http://bit.ly/SPPB4k

10. SEO & Web Performance
• Faster Sites Rank Higher
• Faster is Better User Experience
• http://bit.ly/1Ezmko6
• Mobile First Web Applications Rank Higher
• Call Mobilegeddon
• http://bit.ly/1JFpsmE

11. Time is Money
• Faster Sites Have Higher Conversion Rates
• WalMart - http://bit.ly/S1fHSZ
• Google – http://bit.ly/WajJbB
• Amazon – http://bit.ly/S3UoAj
• ShopZilla - http://bit.ly/RIQMDM

12. WalMart
Folks at Walmart knew their pages were slow. As a for instance, initial
measurement showed that an item page took about 24 seconds to load
for the slowest 5% of users. Why? The usual culprits: too many page
elements, slow third-party scripts, multiple hosts (25% of page content
is served by partners, affiliates, and Marketplace), and various best
practice no-nos
http://bit.ly/WajJbB

13. Google’s ½ Second
Half a second delay caused a 20% drop in traffic. Half a second delay
killed user satisfaction.
The lesson, Marissa said, is that speed matters. People do not like to
wait. Do not make them.
http://bit.ly/TPPhUp

14. Fast Facts
• 57% Will Abandon a Slow Site After 3 Seconds
• We Have to Concentrate 50% Harder For Slow Sites
• 78% Have Felt Stress or Anger With Slow Sites
• 44% Say Slow Sites Make Them Anxious
• 4% Have Thrown Their Phone
http://bit.ly/SuBLDR

15. Web Sites Are Getting Fat and Out of Shape
http://httpArchive.org
99 Files Requests – 2+MB
18 JavaScript Files - 318KB
6.4 CSS Files – 61KB
53 Images – 1.3MB
38 TCP Connections
17 Domains
46% Cacheable

16. Web Sites Are Getting Larger

17. http://bit.ly/1zXjWqB

18. That's Great But I Work
in the Enterprise

19. Performance IS Relevant
• Do you really want to waste $$$
• You want to make co-workers hate you?
• And Possibly Throw a Phone at You
• Remember the Physiological Stats?
• Slow Web Apps Have Higher Data Entry Error Rates
• Due to Increase Cognitive Load
• Oh And You Are Going Mobile
• And You Already Have, Even If You and Your Boss Does Not Acknowledge It

20. http://bit.ly/16zFCXL

21. Good Code Is Cheaper
•Performance Best Practices Lead To:
•Well Structured Code
•Smaller Code
• Easier Maintenance
• Fewer Bugs
•Encourages Development Best Practices
•Encourages Discipline

22. OK How Do I Figure
Out How to Fix
Things?

23. Measure
•Load Time
•Page Speed Index
•Rendering
•Run-Time Performance

24. Set A Performance Budget
•Tim Kadlec
•http://bit.ly/1CUAfGx
•Typically Load Time
• Shoot for < 2 Seconds Over Broadband
• < 1 Second My Standard
• Page Weight
• What Doe My Web Site Cost? - http://whatdoesmysitecost.com/
• HTTP Chattiness

25. webpagetest.org
• Online Tool
• Identifies Common Performance Issues
• Must be Public URL
http://bit.ly/1dibffr

26. http://bit.ly/1dibffr

27. webpagetest.org – film strip view

28. YSlow Rules
1. Minimize HTTP Requests
2. Use a Content Delivery Network
3. Avoid empty src or href
4. Add an Expires or a Cache-Control Header
5. Gzip Components
6. Put StyleSheets at the Top
7. Put Scripts at the Bottom
8. Avoid CSS Expressions
9. Make JavaScript and CSS External
10. Reduce DNS Lookups
11. Minify JavaScript and CSS
12. Avoid Redirects
13. Remove Duplicate Scripts
14. Configure ETags
15. Make AJAX Cacheable
16. Use GET for AJAX Requests
17. Reduce the Number of DOM Elements
18. No 404s
19. Reduce Cookie Size
20. Use Cookie-Free Domains for
Components
21. Avoid Filters
22. Do Not Scale Images in HTML
23. Make favicon.ico Small and Cacheable
http://yhoo.it/W7BFIw

29. 1. Add A Fav Icon – Eliminate 404s
“Most of your scaling
problems wont be
glamorous“
Mike Krieger
http://bit.ly/QeKZsO

30. Make FavIcon Small and Cacheable
• Don’t Return 404
• YSlow Rule #18
• Make Sure Its Compatible
• PNG/ICO
• It Carries Cookie Weight
• Instagram Lesson #1
http://bit.ly/RUXEiL

31. 2.Use a CDN
• Globally Distributes Resources Closer to Client
• Was Expensive
• Amazon CloudFront & Azure cost pennies a month

32. 3. Far Future Expires Header
• Lets the Browser Cache Resources Locally
• Eliminates Future Http Requests
• The Fastest Http Request is the one not made
• Only Updates Resource if Changed on Server

33. 4. Use LocalStorage For Storage & Caching
• Allows You to Keep Data Locally in a Hash Table
• localStorage
• sessionStorage
• Approximately 5-10MB
• Replace Cookies
• Great For Caching
• Use IndexDB for Larger Data Sets

34. AJAX Caching
• Checks localStorage Before Making AJAX Call
• Stores Data in localStorage with Expiration Value
• Radically Reduces Http Requests
• Radically Improves Performance
• The Fastest AJAX Request is the One That is Never
Made.

35. 5. No More Cookies
• Cookies Add Weight
• Place Resources (img/css/js) on
Cookieless Domains
• CDNs Are Great For No Cookies
• Consider Local Storage Instead

36. SWA & Cookies
36

37. Impact of Cookies on Response Time

38. Is 78ms A Big Deal???
• Remember 95 Files
• 95 * 78ms = 7410ms or 7+ Seconds
• 1248ms when considering 6 parallel connections
• Does Cause Delay
• Parallel Downloads Help Overall Time
• Don’t Use 95 Files, Duh

39. 6. Optimize Images
• Images are Too Large
• PNGCrush, Kraken.io
• Image Sprites
• Glyph Fonts
• Data URIs
• CSS Rules

40. • CSS Sprites
• Consider Gyph/Icon Font
• CSS Gradients, Border Radius, Shadows
• Text
• This is a 30KB Image – Possible Change to 0KB*

41. 7. Bundle & Minify CSS & JavaScript
• Eliminate Excess HTTP Requests
• Reduces Data Footprint
• This is a Release or Production Version
• Shoot for a Single JS and a Single CSS file in Production

42. 7a. Inline Critical CSS & Remove Unused CSS
• Inlining Critical CSS Enables Instant Rendering Experience
• Remove Unused CSS
• UNCSS Module
• Identify Critical CSS
• Example: Most Bootstrap Sites Use <10% of Bootstrap
• Bootstrap Adds up to 600kb to Page Weight

43. Use A Client Build System
• Bundling & Minification is OK
• Grunt Is Very Easy & Extensive
• Validate Scripts
• Combine & Minify Scripts
• Validate CSS
• Combine & Minify CSS
• Critical CSS
• UNCSS
• Many Other Tasks
• Gulp, Broccoli are also good tools
• http://bit.ly/1kcrpuo

44. Grunt.js

45. 8. Gzip Text Content
• Browsers Support Gzip & Deflate Algorithms
• Reduces Text Base Content Size
• Makes it Easier to Traverse Intertubes
• 14kb Critical Packet Size
• This is due to HTTP’s Slow Start
• This is the Goal for Optimal Mobile Performance

46. Configure Gzip in IIS

47. Configure Gzip in Amazon S3 | CloudFront

48. 9. CSS @ Top – JavaScript @ Bottom
• CSS is Read & Evaluated to Build CSSOM
• Late CSS causes Browser to ‘Start All Over’
• JavaScript is a Blocking Action
• Browser Stops Everything
• Script Must Be Loaded
• Script Must Be Evaluated
• Use Async & Defer Attributes

49. 10. External CSS & JavaScript
• Allows Resources to be Cached Independently of Markup
• Reduces Page Weight
• Reduces Chance of Duplicate Code
• Can Be Bundled & Minified

50. Critical Rendering Path

51. Bonus – Use AppCache
• <html lang="en-US" manifest="ie11WebSite.appcache">
• Stores Resources Locally in a Sandbox Cache for the Domain
• Available Offline
• Has an Event API

52. Bonus – Use AppCache
CACHE MANIFEST
# version 0.07
CACHE:
#images
favicon.ico
img/purple-bkg.jpg
#css
css/site.min.css
#js
js/applib.js
NETWORK:
#http://example.com/api/
#http://api.rottentomatoes.com/api/public/v1.0/
FALLBACK:
#http://content9.flixster.com/movie/*.jpg /img/offline-poster.png