WebDev:FrontendCodeStandards

Browser Requirements

Support Levels

• A grade:
  • Full functionality and layout support
  • Minor inconsistencies between browsers is tolerable
• B grade:
  • Larger rendering issues allowed
  • Fallback to basic html from dhtml/ajax where necessary
• C grade
  • Send down just HTML
  • Degrade to base interactions

If it's not on the chart, we don't support it.

Mobile Devices

	Support Level
Mobile IE	A-Grade
Fennec	A-Grade
Opera Mobile	A-Grade

Internal Tools

	Linux	Win XP	Vista	OS 10.5	OS 10.6
Fx 3.5	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Fx 3	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade

Full Support

(primary goal of website is to drive Firefox downloads and/or offer technical support)

	Linux	Win7	Win XP	Vista	OS 10.5	OS 10.6
IE 8		A-Grade	A-Grade	A-Grade
IE 7			A-Grade	A-Grade
IE 6			A-Grade
Fx 3.5	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Fx 3	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Fx 2	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Safari 4		A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Safari 3		A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Opera 10	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Opera 9	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Chrome		A-Grade	A-Grade	A-Grade
Gecko based	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade

Latest Support

(primary audience of website is Firefox users)

	Linux	Win7	Win XP	Vista	OS 10.5	OS 10.6
IE 8		A-Grade	A-Grade	A-Grade
IE 7			A-Grade	A-Grade
Fx 3.5	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Fx 3	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Fx 2	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade
Safari 4		A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Safari 3		A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Opera 10		A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Opera 9	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade	A-Grade
Chrome		A-Grade	A-Grade	A-Grade
Gecko based	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade	B-Grade

Other Support

• New Sites/Projects: Progressive enhancement for advanced functionality
• Current Sites: make new functionality degrade, don't rewrite current code
• Need to work on accessibility! (ex: AMO Control Panel)

QA Requirements

QA should test and file bugs appropriately for the browser support chart that applies to each site.

Accessibility Requirements

• Add basic ARIA support where appropriate

Code Standards

• Layered semantic markup
  • Semantic class/id names and appropriate HTML tags for content
  • No inline CSS & JS unless absolutely necessary
  • Progressive enhancement (see bolded QA requirements)
• HTML:
  • HTML5 doctype. Safe to use for all browsers.
  • Pages must validate. Not a strict requirement. Some layouts can't be achieved without a few errors.
  • Use most meaningful tags for content
  • Images/bg images with text in them must have alternate textual representation (alt text or text positioned offscreen for screenreaders). Avoid these due to L10n difficulties anyway.
• CSS:
  • No separate stylesheets for any browser and no conditional statements.
    • This might be necessary for some layouts. Reserved for worst case scenarios.
  • For new sites, look into YUI Fonts & Reset, this will reduce browser layout differences
  • Semantic classnames
  • Don't use position: absolute unless absolutely necessary
  • Use least amount of selectors possible to allow for overriding
  • Don't use !important (see above)
  • Specify font sizes in EMs or %
  • Clear floats with zoom:1 & content:after
  • Hide content for screen readers with position:absolute and position offscreen. Display:none hides content from screen readers.
  • Design layouts to stretch according to their contents (good for localization and good for font-resizing)
  • Avoid selectors that are native element names (i.e. don't style on "div" or "p") except when resetting.
  • Specify in comments the scope of generic sounding class names (what does .block mean and where is it applied? one page or multiple pages?)
    • Try avoiding generic class names altogether
• JS
  • Don't pollute the global namespace (put all functions into objects/closures)
  • Use Module pattern for singletons? (http://yuiblog.com/blog/2007/06/12/module-pattern/)
  • Use .prototype for objects
  • Use jQuery
    • Very fast & light
    • If you need another library, please concatenate & use as little as possible
  • Make JS reusable as best as possible.
  • var your variables
  • Use JSlint : http://www.jslint.com/

Performance Standards

Page requirements

• Min score of B on homepage and 1 other 'major' page
• ~400k max page size

Recommendations

• Follow Yahoo!'s 34 rules http://developer.yahoo.com/performance/rules.html
• Follow these best practices: http://developer.yahoo.net/blog/archives/2008/01/the_7_habits_fo.html
• Sprite images
• Concat and minify JS & CSS with
  • YUI Compressor (http://www.julienlecomte.net/blog/2007/08/13/)
  • or Minify (http://code.google.com/p/minify/)
• No more images in the DB!
• Max 3s load time for all pages (tracked via Gomez)
• Min Xms for page to execute?
• Use ySlow to see where pages can be improved

(see Webtools:Scalability for an overview of tools/infrastructure)

Security Standards

To be branched off into separate document

Also IT's responsibility, we should work with them together on this

• Protect against cross-site request forgeries with crumbs (http://developer.yahoo.com/security/)
• Filter all input (SQL, HTML, JS, CSS)
• Verify user has permissions on content they are editing/deleting
• Don't include JS from 3rd party domains
• Read http://phpsec.org/projects/guide/
• More?