Mobile Web Speed Bumps

22 483 vues

Publié le

As browsers explode with new capabilities and migrate onto devices users can be left wondering, “what’s taking so long?” Learn how HTML, CSS, JavaScript, and the web itself conspire against a fast-running application and simple tips to create a snappy interface that delight users instead of frustrating them.

Publié dans : Technologie, Business
2 commentaires
37 j’aime
Statistiques
Remarques
Aucun téléchargement
Vues
Nombre de vues
22 483
Sur SlideShare
0
Issues des intégrations
0
Intégrations
4 786
Actions
Partages
0
Téléchargements
205
Commentaires
2
J’aime
37
Intégrations 0
Aucune incorporation

Aucune remarque pour cette diapositive

Mobile Web Speed Bumps

  1. 1. Mobile Web Speed Bumps Dont let these problems slow your app downNicholas C. ZakasPresentation Architect, Yahoo!@slicknet
  2. 2. Whos this guy? Presentation Contributor, Architect Creator of YUI TestAuthor Lead Author Contributor Lead Author
  3. 3. http://www.flickr.com/photos/veggiefrog/3435380297/
  4. 4. http://www.flickr.com/photos/fkmr/48131497/
  5. 5. ➔ Latency ➔ Device ➔ Testinghttp://www.flickr.com/photos/veggiefrog/3435380297/
  6. 6. Network latency is a time delay in delivering data to the client device Data transmission over the air always has latency
  7. 7. http://developer.yahoo.com/blogs/ydn/posts/2009/10/a_engineers_gui/
  8. 8. http://developer.yahoo.com/blogs/ydn/posts/2009/10/a_engineers_gui/
  9. 9. DNSWeb
  10. 10. DNSCell Co. Web
  11. 11. replace em with CSS where possibleImages http://www.flickr.com/photos/calliope/83867359/
  12. 12. Use only CSS for simple imagesGradients | Rounded Corners | Drop Shadows | Text Shadows
  13. 13. Browser creates images = 0 HTTP requests
  14. 14. No Images!-webkit-border-radius: 16px;border-radius: 16px;-webkit-box-shadow: 0 8px 4pxrgba(192,192,192,0.5);box-shadow: 0 8px 4px rgba(192,192,192,0.5);background-image:-webkit-gradient(linear, 0%0%, 0% 90%, from(rgba(64,64,64,0.75)),to(rgba(192,192,192,0.9)));http://www.schillmania.com/content/entries/2009/css3-and-the-future/
  15. 15. replace em with CSS where possibleImages put em inline using data URIs http://www.flickr.com/photos/calliope/83867359/
  16. 16. http://www.nczonline.net/blog/2009/10/27/data-uris-explained/
  17. 17. data:[<mime type>][;charset=<charset>][;base64],<encoded data>
  18. 18. data:image/gif;base64,R0lGODlhEAAOALMAAOazToeHh0tLS/7LZv/0jvb29t/f3//Ub//ge8WSLf/rhf/3kdbW1mxsbP//mf///yH5BAAAAAAALAAAAAAQAA4AAARe8L1Ekyky67QZ1hLnjM5UUde0ECwLJoExKcppV0aCcGCmTIHEIUEqjgaORCMxIC6e0CcguWw6aFjsVMkkIr7g77ZKPJjPZqIyd7sJAgVGoEGv2xsBxqNgYPj/gAwXEQA7
  19. 19. <img src="data:image/gif;base64,R0lGODlhEAAOALMAAOazToeHh0tLS/7LZv/0jvb29t/f3//Ub//ge8WSLf/rhf/3kdbW1mxsbP//mf///yH5BAAAAAAALAAAAAAQAA4AAARe8L1Ekyky67QZ1hLnjM5UUde0ECwLJoExKcppV0aCcGCmTIHEIUEqjgaORCMxIC6e0CcguWw6aFjsVMkkIr7g77ZKPJjPZqIyd7sJAgVGoEGv2xsBxqNgYPj/gAwXEQA7"> Data URIs can be embedded in HTML No more extra HTTP requests for images!
  20. 20. .icon1 { background: url(data:image/png;base64,<data>) no-repeat;}.icon2 { background: url(data:image/png;base64,<data>) no-repeat;} Data URIs can be embedded in CSS No more extra HTTP requests for images!
  21. 21. http://www.flickr.com/photos/12714995@N03/5069508897/ But I already have so many CSS files that reference images!
  22. 22. http://github.com/nzakas/cssembed
  23. 23. java -jar cssembed-0.3.6.jar -o styles_data_uris.css styles.css
  24. 24. Data URIs are well-supported across smartphone browsers
  25. 25. http://www.flickr.com/photos/drb62/2543573955/Data URIs not supported by• Nokia Series 40• Myriad/OpenWave• Internet Explorer Mobile• Motorola Browser
  26. 26. replace em with CSS where possibleImages put em inline using data URIs if all else fails, make em small http://www.flickr.com/photos/calliope/83867359/
  27. 27. 320x480 768x1024
  28. 28. Large images not needed
  29. 29. http://tinysrc.net/
  30. 30. <imgsrc="http://i.tinysrc.mobi/http://example.com/myimage.png"alt="My image"> Automatically resizes images to viewport
  31. 31. <imgsrc="http://i.tinysrc.mobi/320/240/http://example.com/myimage.png" alt="My image" width="320" height="240"> Automatically resizes image to 320x240
  32. 32. Put JavaScript and CSS inline** But only on first page view
  33. 33. http://m.bing.com
  34. 34. Request #1 146 KB Request #2 14 KB
  35. 35. RMSM=JApp.Home.DE384EBF~JUX.UXBaseControls.65310C41~JUX.FrameworkCore.53E1E635~JUX.PublicJson.540180A4~JUX.Compat.0907AAD4~JUX.MsCorlib.172D90C3~CUX.SiteLowRes.C8A1DA4E~CApp.Home.FD66E1A3~CUX.Keyframes.B8625FEE~CUX.Site.18BDD93
  36. 36. RMSM= Japp.Home.DE384EBF~ JUX.UXBaseControls.65310C41~ JUX.FrameworkCore.53E1E635~ JUX.PublicJson.540180A4~ JUX.Compat.0907AAD4~ JUX.MsCorlib.172D90C3~ CUX.SiteLowRes.C8A1DA4E~ Capp.Home.FD66E1A3~ CUX.Keyframes.B8625FEE~ CUX.Site.18BDD93
  37. 37. First Request<style data-rms="save" id="CUX.Site.18BDD936"rel="stylesheet" type="text/css">...</style><script data-rms="save"id="JUX.UXBaseControls.65310C41"type="text/javascript">...</script>
  38. 38. Second Request<scripttype="text/javascript">RMS.Load(CUX.Site.18BDD936)</script><scripttype="text/javascript">RMS.Load(JUX.UXBaseControls.65310C41)</script>
  39. 39. How It Works1. On first page load, inline all scripts and styles2. Extract scripts and styles from page and store in localStorage3. Set cookie with Ids of the scripts and styles in localStorage4. On next page load, look at cookies5. Output scripts instructing the browser to load that resource from localStorage
  40. 40. Extracting From The DOM//extract inline script contentsvar scriptNode = document.querySelector("script");var scriptText = scriptNode.text;//extract inline style contentsvar styleNode = document.querySelector("style");var styleText = styleNode.innerHTML;
  41. 41. 40% of time on redirect Download Redirect
  42. 42. ➔ Latency ➔ Device ➔ Testinghttp://www.flickr.com/photos/veggiefrog/3435380297/
  43. 43. iPad 2 Droid iPhone 4 Droid X Incredible Mac MiniProcessor 2.2-2.4 GHz 1 GHz 1 GHz 1 GHz 1 GHzRAM 2 GB 512 MB 512 MB 512 MB 512 MBStorage 320-500 GB 16-32 GB 8 GB 8 GB 16-64 GB
  44. 44. http://www.flickr.com/photos/antonfomkin/3046849320/
  45. 45. Keep JavaScript small
  46. 46. All browsers now have optimizing JavaScript enginesTracemonkey/ V8 Nitro Chakra KarakanJaegarMonkey (all) (4+) (9+) (10.5+) (3.5+)
  47. 47. http://ie.microsoft.com/testdrive/benchmarks/sunspider/default.html
  48. 48. http://jeftek.com/1942/motorola-xoom-sunspider-results/
  49. 49. JavaScript Execution = CPU Processing =Battery Consumption
  50. 50. Dont even think about using JavaScript-based animations CSS-based onlyhttp://www.flickr.com/photos/eschipul/260392040/
  51. 51. Hardware Acceleration (Compositing) http://www.flickr.com/photos/pagedooley/3493267443/
  52. 52. Hardware accelerated CSS animations
  53. 53. No hardware acceleration before Android 3.0
  54. 54. Be careful with CSS
  55. 55. Trigger Compositing.some-element { -webkit-transform: rotate(0);} Any transform works!
  56. 56. http://www.flickr.com/photos/kkoshy/2825871499/Non-composited elements work as you expect
  57. 57. http://www.flickr.com/photos/kkoshy/2825871499/Composited elements become images in memory
  58. 58. http://www.flickr.com/photos/kkoshy/2825871499/Each composited element takes up width x height x 4 bytes
  59. 59. Too many composited elements = High memory usage = Slow-moving UI
  60. 60. iOS doesnt support memory paging
  61. 61. https://bugs.webkit.org/show_bug.cgi?id=56917
  62. 62. CSS Gradients(Keep em small)
  63. 63. CSS Gradients(i.e. no full page backgrounds)
  64. 64. Radial gradients are heavy Use caution
  65. 65. If your app is sluggish, tryreplacing CSS gradients with data URIs or images
  66. 66. Keep the DOM smallRemove unused elements
  67. 67. ➔ Latency ➔ Device ➔ Testinghttp://www.flickr.com/photos/veggiefrog/3435380297/
  68. 68. d ! p e a p t c no r y m oM e
  69. 69. http://www.blaze.io/mobile/
  70. 70. http://stevesouders.com/mobileperf/mobileperfbkm.php
  71. 71. http://jdrop.org
  72. 72. Summary
  73. 73. ➔ Latency ➔ Device ➔ Testinghttp://www.flickr.com/photos/veggiefrog/3435380297/
  74. 74. Images | JavaScript | CSS | DOM
  75. 75. BalanceThis is a new frontier.The investigation has only juststarted.Test, test, test.Share. http://www.flickr.com/photos/brent_nashville/201143283/
  76. 76. Etcetera• My blog: www.nczonline.net• Twitter: @slicknet• These Slides: http://slideshare.net/nzakas/

×