Professional Frontend Engineering

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Professional Frontend Engineering

  1. 1. Professional Frontend Engineering Nate Koechley Senior Frontend Engineer Yahoo!natek@yahoo-inc.com | developer.yahoo.com/yui nate.koechley.com/blog | “natekoechley”
  2. 2. Why this topic?
  3. 3. • Put a stake in the ground.• Reiterate our values.• Advocate the discipline.• Nurture a healthy Web.
  4. 4. HistoricalPerspective
  5. 5. Historical Our BeliefsPerspective & Principles
  6. 6. Historical Our BeliefsPerspective & Principles KnowledgeAreas & Best Practices
  7. 7. Historical Our BeliefsPerspective & Principles Knowledge Why It AllAreas & Best Matters Practices
  8. 8. HistoricalPerspective
  9. 9. Year = 2001
  10. 10. Age = 7 years
  11. 11. Employees = 3000
  12. 12. FrontendEngineers = 0
  13. 13. So?
  14. 14. 2001First frontend engineering specialists hired.
  15. 15. 2008~700 professional frontend engineers spread across Y! offices worldwide. And hiring!!!
  16. 16. 2001Font tags & nested tables. Static interface.
  17. 17. 2008Semantic & accessible markup.Rich DHTML & Ajax behavior.More content. Same fast speed.
  18. 18. 2001Available and accessible to everyone.
  19. 19. 2008Available and accessible to everyone.
  20. 20. 2001Plain but predictable.
  21. 21. 2008Highly visual and adaptive, but still dependable.
  22. 22. 2001Modest user expectations.
  23. 23. 2008 Sophisticated, broad, andnon-trivial user expectations.
  24. 24. 2001Intersection of design and development still vague.
  25. 25. Now Professional Frontend Engineers focused at the intersection of design anddevelopment is a best practice.
  26. 26. —Irene Au, SVP of UED at Yahoo!
  27. 27. “In 2001, with developments in advanced JavaScript and DHTML, we knew the web experience would evolve beyond the staticpages we were producing. We brought in webdevelopers to help us pioneer Yahoo’s offerings to include a more dynamic, interactive experience for our users.” —Irene Au, SVP of UED at Yahoo!
  28. 28. —Irene Au, SVP of UED at Yahoo!
  29. 29. “... Another motivation was to bring in a disciplined frontend programming practice to Yahoo. Before then, thepresentation, behavior, and structure ofour pages were not separate, which led to many challenges and inefficiencies indesigning and developing our products.” —Irene Au, SVP of UED at Yahoo!
  30. 30. “The Framers of the Web saw browser differencesas beneficial and believed that visitors shouldchoose how their browser displays the page...”
  31. 31. “...I wanted more control so I threw my HTML book in the trash and started from scratch.”
  32. 32. The Web is still sick.
  33. 33. Frontend Engineers arethe Web’s Radiologists
  34. 34. Question:What is FrontendEngineering?
  35. 35. Answer:We write softwarein JavaScript, CSS,and HTML & more...
  36. 36. Answer:We tell browserswhat to do.
  37. 37. Answer:We’re responsiblefor “view source”
  38. 38. The Yahoo! Stack Pages & modules 95% HTML, 5% PHP Display logic & APIs 50% HTML, 50% PHP Specific PHP biz logic 90% PHP, 10% Text Generic PHP functions & libs 100% PHP C/C++ Libraries. 90% C/C++, 10% PHP
  39. 39. The Yahoo! Stack Pages & modules Frontend 95% HTML, 5% PHP Display logic & APIs 50% HTML, 50% PHP Specific PHP biz logic 90% PHP, 10% TextGeneric PHP functions & libs 100% PHP Backend C/C++ Libraries. 90% C/C++, 10% PHP
  40. 40. The Yahoo! Stack Pages & modules Frontend 95% HTML, 5% PHP Display logic & APIs 50% HTML, 50% PHP Specific PHP biz logic 90% PHP, 10% TextGeneric PHP functions & libs 100% PHP Backend C/C++ Libraries. 90% C/C++, 10% PHP
  41. 41. SIMPLE?
  42. 42. no.
  43. 43. server
  44. 44. (X)HTML server
  45. 45. (X)HTML Specification server
  46. 46. (X)HTML Specification Implementation server
  47. 47. (X)HTML Specification Implementation Bugs server
  48. 48. (X)HTML Specification Implementation Bugs [ Theory / Practice ] server
  49. 49. CSS BOM API(X)HTML DOM JavaScript DOM API Specification Data Transport data: custom, xml, mixed: new xhtml Implementation json behavior: js Bugs [ Theory / Practice ] server
  50. 50. Safari Firefox Opera IE5, 6, 7 Firefox Opera 10,000+ UAs Macintosh Windows Linux, Unix, Mobile CSS BOM API (X)HTML DOM JavaScript DOM API Specification Data Transport data: custom, xml, mixed: new xhtml Implementation json behavior: js Bugs [ Theory / Practice ] server
  51. 51. Safari Firefox Opera IE5, 6, 7 Firefox Opera 10,000+ UAs Macintosh Windows Linux, Unix, Mobile CSS BOM API (X)HTML DOM JavaScript DOM API Specification data: custom, xml, mixed: new xhtml, Data Transport Implementation behavior: js json Defects [ Theory / Practice ] server
  52. 52. Safari Firefox Opera IE5, 6, 7 Firefox Opera 10,000+ UAs Macintosh Windows Linux, Unix, Mobile knowledge areas: 7 CSS (X)HTML dimensions: xJavaScript DOM 4 BOM API DOM API platforms: x 3 Specification data: custom, xml, mixed: new xhtml, browsers perDefects platform: x 4 Data Transport Implementation behavior: js json rendering modes: x 2 [ Theory / Practice ] server =672
  53. 53. usability, internationalization, localization, visual design, accessibility, information architecture, security, build processes, performance,benchmarking, devices, portability
  54. 54. from Lifted©2007 Pixar Animation Studios
  55. 55. Different from Backend because we:• Can’t compile.• Can’t trust.• Can’t predict.• Can’t install or store.• Can’t hide anything!
  56. 56. Douglas Crockford on browsers: “The most hostile software development environment imaginable.”
  57. 57. If your business is online... your value depends on Frontend Engineering.
  58. 58. Elegant algorithms benefit users through interfaces built by Frontend Engineers.
  59. 59. Every gorgeous design isbrought to life by Frontend Engineers.
  60. 60. Frontend engineers give sites strength & resilience, appearance & form, and functionality & interactivity.
  61. 61. ...which is why professional frontend engineering is critical for success.
  62. 62. Historical Our BeliefsPerspective & Principles
  63. 63. Four Guiding Principles
  64. 64. 1) Availability
  65. 65. Availability:Maximize availability, accessibilityand utility of content and servicesfor all users worldwide.
  66. 66. 2) Openness
  67. 67. Openness:Share. Learn. Support. Advocate.We benefit from a healthy Internet.
  68. 68. 3) Richness
  69. 69. Richness:Provide, but not too much.Layer endlessly.Remember we are not average.
  70. 70. 4) Stability
  71. 71. Stability:The Web is young.Invest in quality.Prepare for the future.
  72. 72. Four Guiding Principles• Availability• Openness• Richness• Stability
  73. 73. Three Core Techniques
  74. 74. 1) Graded Browser Supporthttp://developer.yahoo.com/yui/articles/gbs/
  75. 75. “Support” does not mean identical.
  76. 76. “Support” is not a binary choice.
  77. 77. Three Support Grades
  78. 78. Three Support GradesC-Grade • Blacklist (of incapable browsers) • Withhold CSS & JavaScript
  79. 79. Three Support GradesC-Grade • Blacklist (of incapable browsers) • Withhold CSS & JavaScriptA-Grade • Whitelist (of capable browsers tested) • Serve CSS & JavaScript
  80. 80. Three Support GradesC-Grade • Blacklist (of incapable browsers) • Withhold CSS & JavaScriptA-Grade • Whitelist (of capable browsers tested) • Serve CSS & JavaScriptX-Grade • Everybody else. • Serve CSS & JavaScript
  81. 81. A-Grade Supporthttp://developer.yahoo.com/yui/articles/gbs
  82. 82. C-Grade Experience
  83. 83. A-Grade Experience
  84. 84. C-Grade Experience
  85. 85. A-Grade Experience
  86. 86. 2) ProgressiveEnhancement
  87. 87. Rules of Progressive Enhancement
  88. 88. Rules of Progressive Enhancement• Enrich content with thorough, explicit markup.
  89. 89. Rules of Progressive Enhancement• Enrich content with thorough, explicit markup.• Test core functionality with HTML only.
  90. 90. Rules of Progressive Enhancement• Enrich content with thorough, explicit markup.• Test core functionality with HTML only.• Enhance layout via externally linked CSS.
  91. 91. Rules of Progressive Enhancement• Enrich content with thorough, explicit markup.• Test core functionality with HTML only.• Enhance layout via externally linked CSS.• Enhance behavior via externally linked unobtrusive JavaScript.
  92. 92. Rules of Progressive Enhancement• Enrich content with thorough, explicit markup.• Test core functionality with HTML only.• Enhance layout via externally linked CSS.• Enhance behavior via externally linked unobtrusive JavaScript.• Respect end-user browser preferences.
  93. 93. Flipped definition of“graceful degradation”
  94. 94. 3) Unobtrusive JavaScripthttp://onlinetools.org/articles/unobtrusivejavascript/
  95. 95. Rules of Unobtrusive JavaScript
  96. 96. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.
  97. 97. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.• Don’t depend on or trust JavaScript.
  98. 98. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.• Don’t depend on or trust JavaScript.• Poke objects before using them.
  99. 99. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.• Don’t depend on or trust JavaScript.• Poke objects before using them.• Write JavaScript, not dialects.
  100. 100. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.• Don’t depend on or trust JavaScript.• Poke objects before using them.• Write JavaScript, not dialects.• Mind your manners with vars & scope.
  101. 101. Rules of Unobtrusive JavaScript• No JavaScript in HTML documents.• Don’t depend on or trust JavaScript.• Poke objects before using them.• Write JavaScript, not dialects.• Mind your manners with vars & scope.• Support multiple event triggers.
  102. 102. Don’t Break the Web!href=“#”href=“javascript:foo()”onclick=“foo()”
  103. 103. Three Core Techniques• Graded Browser Support• Progressive Enhancement• Unobtrusive JavaScript
  104. 104. Making Decisions
  105. 105. Making Decisions (1)1. Do what is standard. if impossible, then:2. Do what is common. if impossible, then:3. Do what it takes.
  106. 106. Making Decisions (2)1. Do what is simple. ✚2. Do what is flexible & progressive. ✚3. Do what is open.
  107. 107. Making Decisions (3)• Remember you have multiples audiences to satisfy: • Users • Developers • Machines
  108. 108. Historical Our BeliefsPerspective & Principles KnowledgeAreas & Best Practices
  109. 109. 8 Areas of Focus1. HTML 6. Performance2. CSS 7. Infrastructure & Process3. JavaScript 8. Tooling4. Accessibility5. Internationalization
  110. 110. oc usF #1 HTML
  111. 111. Focus: Be thorough.
  112. 112. <label>
  113. 113. <fieldset>
  114. 114. <cite>
  115. 115. <caption>
  116. 116. <thead>
  117. 117. <th scope=”row” abbr=”ManU”>
  118. 118. <ins datetime=”2008-05-30”>
  119. 119. Aim for permanence.
  120. 120. Switching costs are rising.
  121. 121. oc usF #2 CSS
  122. 122. Focus on the left side.
  123. 123. selector: declaration;
  124. 124. selector: declaration;
  125. 125. Focus: Specificity great selectors are anexpression of professionalism
  126. 126. h1: declaration;
  127. 127. #mod h1: declaration;
  128. 128. div#mod h1: declaration;
  129. 129. body.cart #mod h1.class a: declaration;
  130. 130. #mod ul li li: declaration;
  131. 131. Focus: Maintenance think about how sites age
  132. 132. oc usF #3 JavaScript
  133. 133. JavaScript• Quality• Security
  134. 134. 1) Quality
  135. 135. Linting• Use programs like JSLint (jslint.org) to confirm the quality of your code.• Adopt the idioms it promotes to improve your code quality.
  136. 136. Unit Testing w/ YUI Test• Rapid creation of test cases via simple syntax.• Advanced failure detection for methods that throw errors.• Grouping of related test cases using test suites.• Asynchronous tests for testing events and Ajax communication.• DOM Event simulation in all A-grade browsers.
  137. 137. Profiling• Learn where to improve your code.• Programmatically retrieve profiling information as the application is running.• Determine unit-testing success based on profiling results.
  138. 138. JavaScript Pollution• Do not mutate JavaScript itself.• Do protect yourself from browsers.• Minimize touchpoints between authors and vendors so vendors can iterate faster.
  139. 139. 2) Security
  140. 140. JavaScript Security• Beware of XSS• Never Trust Data from the Client• Monitor AdSafe/Caja Developments
  141. 141. oc usF #4 Accessibility
  142. 142. ARIA
  143. 143. Decoupled Events
  144. 144. oc usF #5 Internationalization
  145. 145. Begin serving all .css and .js at UTF-8
  146. 146. @charset "
  147. 147. oc usF #6 Performance
  148. 148. 14 then. 8 more today.
  149. 149. <link> not @import• Because @import overrides the browsers’ native performance sequencing.
  150. 150. Avoid Redirects• 3xx status codes – mostly 301 and 302 HTTP/1.1 301 Moved Permanently Location: http://yahoo.com/newuri• Cache redirects via Expires headers• Redirects are worst form of blocking
  151. 151. Use Cookie-Free Domains For Assets.• Serving static cacheable assets from a distinct domains keeps cookies from riding along with all requests. yimg.com images-amazon.com fbcdn.net
  152. 152. Preload Assets
  153. 153. Preload Assets1. Unconditional preload - always w/ onload Example: google.com’s sprite
  154. 154. Preload Assets1. Unconditional preload - always w/ onload Example: google.com’s sprite2. Conditional preload - based on user action Ex: search.yahoo.com’s Search Assist
  155. 155. Preload Assets1. Unconditional preload - always w/ onload Example: google.com’s sprite2. Conditional preload - based on user action Ex: search.yahoo.com’s Search Assist3. Anticipated preload - give redesigns a boost
  156. 156. Optimize CSS Sprites
  157. 157. Optimize CSS Sprites1. Horizontal alignment is usually smaller than vertical.
  158. 158. Optimize CSS Sprites1. Horizontal alignment is usually smaller than vertical.2. Combine similar colors in a sprite to minimize color count. Only 256 colors can fit in a PNG8.
  159. 159. Optimize CSS Sprites1. Horizontal alignment is usually smaller than vertical.2. Combine similar colors in a sprite to minimize color count. Only 256 colors can fit in a PNG8.3. Avoid unnecessarily large gaps between parts of the sprite.
  160. 160. GET for Ajax Requests• POST is a two-step process.• GET can send in one packet.• Use if possible, but max payload is 2K in IE.
  161. 161. Keep Focusing on Events1. Event Delegation to reduce total number2. Don’t always wait for onLoad • YUI Event has onAvailable, onContentReady, & onDomReady
  162. 162. iPhone Tip• iPhone will not cache assets larger than 25K • That’s 25K uncompressed. • Only 19 total items in cache.• http://yuiblog.com/blog/2008/02/06/iphone- cacheability/
  163. 163. oc usF #7 Infrastructure & Process
  164. 164. Build Process
  165. 165. Documentation
  166. 166. three versions of each member
  167. 167. *.js
  168. 168. *-debug.js
  169. 169. *-min.js
  170. 170. What Is YUI?
  171. 171. oc usF #8 Tooling
  172. 172. Need More Progress.
  173. 173. But there’s been some:• JSLint, JScript Debugger, Firebug, Debug Bar, Fiddler, Charles, HTTP Live Headers, DragonFly, Visual Studio 2008• YUI Logger, YUI Test, and YUI Profiler
  174. 174. Historical Our BeliefsPerspective & Principles Knowledge Why It AllAreas & Best Matters Practices
  175. 175. There’s a lot ofwork to be done.
  176. 176. We need morepeople doing it.
  177. 177. The health of theinternet depends on it.
  178. 178. The health of ourbusinesses and passions depends on it.
  179. 179. We must stay vigilant.
  180. 180. We must defend users.
  181. 181. Go forth with this in mind:
  182. 182. Be TirelessTrendsetters of Quality Be active. Find the way forward. Educate.
  183. 183. Be BelligerentGatekeepers of Quality Do not accept less. Do not cut corners.
  184. 184. Exhibit StubbornEmpathy for Users We’re the last line of defense!
  185. 185. Let’s keep talking... nate@koechley.comhttp://nate.koechley.com/blog “natekoechley”
  186. 186. CC Images Used• http://www.flickr.com/photos/dideo/407360526/sizes/l/• http://www.flickr.com/photos/jenniferbuehrer/113554568/sizes/l/• http://www.flickr.com/photos/peteashton/290691658/sizes/l/• http://www.flickr.com/photos/pedjap/101230548/sizes/o/• http://www.flickr.com/photos/songtuyuri/2200100451/sizes/o/• http://www.flickr.com/photos/dominik99/1403329318/sizes/o/• http://www.flickr.com/photos/cuellar/482993472/sizes/o/
  187. 187. nate@koechley.comhttp://nate.koechley.com/blog natekoechley = twitter,delicious, flickr, tripit, last.fm, linkedin,fireeagle, friendfeed, ... everywhere.

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