a11yTO - Web Accessibility for Developers

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Presented at Toronto Accessibility & Inclusive Design, April 30 2014

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a11yTO - Web Accessibility for Developers

  1. 1. Web Accessibility for Developers a11yTO April 2014 Monika Piotrowicz (@monsika)
  2. 2. Monika Piotrowicz Front End Web Developer Shopify ! @monsika @shopify
  3. 3. I’m just... A regular Front End Developer... ! ! !
  4. 4. So how’d I get here? A short story, starring WCAG 2.0 AA ! ! !
  5. 5. Today • Introduction to accessibility • Techniques you can implement today • Introduction to screen readers & ARIA • Testing tips
  6. 6. Web Accessibility • “When sites are correctly designed, developed and edited, all users can have equal access to information and functionality” - Wikipedia • “Able to be easily obtained or used; easily understood or appreciated” - Oxford Dictionary • Accessibility ~ Usability • All people can use an application, and it should be easy to use for all people;
  7. 7. Accessibility by the #’s rough 1 - CDC Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2011 http://1.usa.gov/M6tObC (under 65/over 65) 2 - Range worldwide prevalence of red-green color deficiency among men, 2012 http://1.usa.gov/M6tKsz Group Population Vision Problems 3-10% Colorblindness 4-8% Physical Functioning 8% Cognitive Difficulty 6% Hearing Difficulty 3-11% Assistive Tools • screen readers • screen magnifiers • keyboard-only • braille display • bumped font size
  8. 8. Me last year...
  9. 9. Go!
  10. 10. WCAG The standard http://www.w3.org/TR/WCAG20/ Understanding WCAG http://www.w3.org/TR/UNDERSTANDING-WCAG20/ Techniques http://www.w3.org/TR/WCAG20-TECHS/ Quick Reference http://www.w3.org/WAI/WCAG20/quickref/ FAQ http://www.w3.org/WAI/WCAG20/wcag2faq.html
  11. 11. Accessibility just a checklist !=
  12. 12. Starting out Early accessibility considerations
  13. 13. First Steps • functional keyboard-only • fallbacks for visual information • well-functioning forms
  14. 14. Keyboard Strategy • obvious focus states (keep those outlines!)
  15. 15. a, a:focus { outline: none; outline: 0; }
  16. 16. Keyboard Strategy ✓ obvious focus states (keep those outlines!) • keypress equivalents for :hover & click() ↳ :focus & keydown()
  17. 17. Keyboard Strategy ✓ obvious focus states (keep those outlines!) ✓ keypress equivalents for :hover & click() ↳ :focus & keydown() • add tabIndex=0 & key events to non-focusable elements
  18. 18. Keyboard Strategy ✓ obvious focus states (keep those outlines!) ✓ keypress equivalents for :hover & click() ↳ :focus & keydown() ✓ add tabIndex=0 & key events to non-focusable elements • avoid keyboard traps & wasting time
  19. 19. Keyboard Strategy ✓ obvious focus states (keep those outlines!) ✓ keypress equivalents for :hover & click() ↳ :focus & keydown() ✓ add tabIndex=0 & key events to non-focusable elements ✓ avoid keyboard traps & wasting time • HTML can get you there, FREE! WebAIM http://bit.ly/M24Da2 Keyboard Events http://bit.ly/M241Br
  20. 20. Wanted: Free Events! <span class="btn-style toggle-trigger">Click to Toggle</span> ! <a href="#" class="btn-style toggle-trigger">Click to Toggle</a> ! <button type="button" class="toggle-trigger">Click to Toggle</ button> Use the button element http://bit.ly/1efaOO1 Links aren’t buttons http://bit.ly/1efaT4o
  21. 21. Visual Considerations • start with a good font size & high contrast • Contrast Checker Tool - http://bit.ly/1eeYZYh (by a fellow Shopify-er) • Chrome Plugin - http://bit.ly/1ljQvFF • Accessible colour palette how-to http://bit.ly/1fnbmJp
  22. 22. Visual Considerations ✓start with a good font size & high contrast • Contrast Checker Tool - http://bit.ly/1eeYZYh (by a fellow Shopify-er) • Chrome Plugin - http://bit.ly/1ljQvFF • Accessible colour palette how-to http://bit.ly/1fnbmJp • don’t rely on colour alone • add legends and texture or symbols
  23. 23. Red-Green Colorblind (Deuteranopia)
  24. 24. Visual Considerations ✓start with a good font size & high contrast • Contrast Checker Tool - http://bit.ly/1eeYZYh (by a fellow Shopify-er) • Chrome Plugin - http://bit.ly/1ljQvFF • Accessible colour palette how-to http://bit.ly/1fnbmJp ✓don’t rely on colour alone • add legends and texture or symbols • all images have a meaningful alt attribute • W3C How to write Alt Text http://bit.ly/1aKwIOg • More from A List Apart http://bit.ly/1aKwRkI
  25. 25. • Every form field includes a real label <label for="[INPUT ID]"> ! ! Forms
  26. 26. ✓ Every form field includes a real label <label for="[INPUT ID]"> • Labels can include help, required, error text ! ! ! Forms
  27. 27. ✓ Every form field includes a real label <label for="[INPUT ID]"> ✓ Labels can include help, required, error text • Provide meaningful message on form error ! ! WebAIM Forms http://bit.ly/1aKw2bM WebAIM Validation http://bit.ly/1aKw6bB Accessible Form Labeling http://bit.ly/1aKw83b Forms
  28. 28. boldly go... The SCREEN READER
  29. 29. TRY ONE!! How else can you expect to build for one? NVDA VoiceOver TalkBack JAWS
  30. 30. How do they work? • announce generated HTML in source order
  31. 31. How do they work? • announce generated HTML in source order
  32. 32. • Use keyboard to navigate and find content • Highly customizable Screen reader 101 ! • 97.6% of screen reader users have JS enabled!1 1 - WebAIM Survey http://bit.ly/1nqd4fp
  33. 33. HTML COUNTS! • Shortcuts drill down to headings, landmarks, lists, links, etc
  34. 34. • Do your main content areas have headings? • Are they descriptive? • Do they follow a hierarchy? (h1 >> h6) Headings Document Outline http://bit.ly/1ef9ScA The Section Element http://bit.ly/1ef9TNN Accessible Headings http://bit.ly/1ef9QBr Using Sections http://bit.ly/1ef9Ykx H1 Blog H2 Recent Articles H3 Article Title H3 Article Title H3 Article Title H2 About Me H3 Contact Me H3 Footer Title • Main way screen reader users navigate
  35. 35. • img with empty alt attribute alt="" SR’s ignore... • :before content, :after content* (sort of) • display: none; • visibility: hidden; * in most cases, so assume it won’t be announced Accessible Icon Fonts http://bit.ly/1efabUP .icon-star:before { content: “★”; } • keep in mind for icons and icon fonts!
  36. 36. • content “hidden” with opacity, z-index, height • off-screen positioning (text-indent, top, left) .sr-only, .visuallyhidden { border: 0; clip: rect(0 0 0 0); height: 1px; margin: -1px; overflow: hidden; padding: 0; position: absolute; width: 1px; } * as seen in HTML5 BP, Twitter Bootstrap, etc. WebAIM Invisible Content http://bit.ly/1efaij8 • CSS clipping* SR’s won’t ignore
  37. 37. Beyond the basics There’s gotta be more to screen readers than just that, right?
  38. 38. • Applied directly to HTML ! • Does not affect styles or non-SR behaviour • Roles, states & properties • Semantic information and better interactions for screen readers ARIA • Part of HTML5 spec HTML5 Spec (W3C) http://bit.ly/1aKxXx5 ARIA Spec (W3C) http://bit.ly/1aKya3f
  39. 39. Roles • Create new semantic meaning for elements via “role-” attribute • Once set, they don’t change <nav role="navigation"> ! <article role="article"> ! <div role="tablist"> ! <div role="combobox">
  40. 40. Landmark Roles Define top-level page sections for easy navigation ! •main •banner •navigation •search •complimentary •contentinfo •form Using Landmarks http://bit.ly/1aKyuyQ WebAIM Landmarks http://bit.ly/1aKytem Role
  41. 41. Landmark Roles Define top-level page sections for easy navigation ! •main ........ <main> •banner ........ <header> •navigation ........ <nav> •search ........ <form> (search form) •complimentary ........ <aside> •contentinfo ........ <footer> •form Role HTML 5 Using Landmarks http://bit.ly/1aKyuyQ WebAIM Landmarks http://bit.ly/1aKytem
  42. 42. Include all content in a landmark wrapper elements with role="landmark"
  43. 43. Widget Roles Semantic meaning to your custom components •tooltip •slider •dialog •tab •progressbar •combobox •menu •alert .. and many more!
  44. 44. ??? <ul class="tab-controls"> <li> <a href="#first-tab" class="current-item">Panel 1</a> </li> <li> <a href="#second-tab" class="current-item">Panel 2</a> </li> <li> <a href="#third-tab" class="current-item">Panel 3</a> </li> </ul> <div id="tab-container"> <div class="tab-panel" id="first-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> <div class="tab-panel" id="second-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> <div class="tab-panel" id="third-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> </div>
  45. 45. ??? <ul class="tab-controls"> <li> <a href="#first-tab" class="current-item">Panel 1</a> </li> <li> <a href="#second-tab" class="current-item">Panel 2</a> </li> <li> <a href="#third-tab" class="current-item">Panel 3</a> </li> </ul> <div id="tab-container"> <div class="tab-panel" id="first-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> <div class="tab-panel" id="second-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> <div class="tab-panel" id="third-tab"> <div class="tab-contents"> <p>Tab Contents</p> </div> </div> </div> <ul class="tab-controls" role="tablist"> <li> <a href="#first-tab" class="current- item" role="tab">Panel 1</a> ! <div id="tab-container"> <div class="tab-panel" id="first-tab" role="tab-panel">
  46. 46. • Describe relationships - between content & between user interactions • updated via JS on UI changes • attribute starts with “aria-” prefix States & Properties <section aria-labelledby="MainHeading"> ! <input aria-label="first 3 digits" aria- describedby="PhoneHelpText"> ! <button aria-expanded="true" class="accordion- toggle" aria-controls="Accordion"> ! <div id=“Accordion" aria-hidden="false" >
  47. 47. Content Relationships • Semantically link labels to content or add them when missing • aria-labelledby, aria-label <section aria-labelledby="HeadingAbout"> <h1 id="HeadingAbout">About Potato Chips</h1> <p>.... Make the most of landmarks http://bit.ly/M1TFSb
  48. 48. Content Relationships • Semantically link labels to content or add them when missing • aria-labelledby, aria-label <nav role="navigation" aria-label="Chip Section Navigation"> <ul> <li> <a href="/types">Flavors</a> </li>
  49. 49. It's just HTML! .elem[aria-hidden = "false"] { display: block; } ! .elem[aria-invalid ="false"] { background: #999; } ! .elem[aria-expanded = "true"] { height: 100%; } The more you know
  50. 50. Putting it all together • jQueryUI https://jqueryui.com/ • Practical ARIA Examples http://bit.ly/1bhMqBg • HTML5 & ARIA Design Patterns http://bit.ly/1bhMlNZ • Accessible Forms with ARIA http://bit.ly/1bhMv7M • Bootstrap Accessibility Plugin (PayPal) http://bit.ly/1bhM8dy
  51. 51. Using ARIA Wisely • ARIA is a bridge, not a replacement. • USE plain HTML if you can • Not magic and makes no promises • Events, focus management, keyboard support, and meaningful structure is still up to you • Only way to know for sure... TEST
  52. 52. ARIA Resources W3C Intro http://www.w3.org/TR/wai-aria-primer/ W3C How-to with design patterns http://www.w3.org/TR/wai-aria-practices/ W3C Supporting Info for developers http://www.w3.org/TR/aria-in-html/ WEBAIM Introduction http://webaim.org/techniques/aria/ Warnings and Perspectives http://alistapart.com/article/the-accessibility-of-wai-aria General Information https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA ARIA Validation http://validator.nu
  53. 53. Testing
  54. 54. Automated Tools • WebAIM WAVE (FF) http://wave.webaim.org/toolbar/ • Accessibility Developer Tools (Chrome) http://bit.ly/1fW0W0A • Web Developer Toolbar (Chrome & FF) http://bit.ly/1dA2JmY • Quail Project quailjs.org
  55. 55. Manual Testing • disable all images • test with just a keyboard • load it in a screen reader • load it in another screen reader 10 Tips anyone can use http://bit.ly/1efaA9N 6 Tests anyone can do http://bit.ly/1efaC1c Does your page make sense? Is it usable ?
  56. 56. Unsolicited Advice • Start small, there’s still a big impact • Prioritize areas/pages • main navigation? • contact us form? • homepage? • Document as you go
  57. 57. Final Thoughts
  58. 58. What I’ve learned • Bake it in, don’t tack it on • Awesome and helpful community • You may find it hard to stop
  59. 59. Behind all these checklists, rules, and regulations, there are people just trying to use your site. So make it useable, for everybody.
  60. 60. Thanks! @monsika
  61. 61. More Resources
  62. 62. More Resources General HTML5 Accessibility http://bit.ly/LVR8YX Accessibility Evaluation Quick Reference http://bit.ly/M6tgCF Mozilla Dev Network ARIA http://mzl.la/M6u9ez Apple Accessibility Resources http://bit.ly/M6tkSL Screen Readers WebAIM Screen Reader Testing http://bit.ly/M6sLIH Videos of Screen Readers In Use http://bit.ly/M6sR39 How browsers interact with screen readers http://bit.ly/M6sUfi NVDA resources WebAIM NVDA http://bit.ly/M6sZj5 WebAIM NVDA Shortcuts http://bit.ly/M6t0n2 Using NVDA and FF to test pages http://bit.ly/M6t6Lu Installing NVDA in a VM http://bit.ly/M6t8D4 VoiceOver resources WebAIM VoiceOver http://bit.ly/M6tbyS Apple VoiceOver User Guide http://bit.ly/M6tolE Apple Developer Accessibility Guide http://bit.ly/M6ttpe JAWS resources WebAIM JAWS http://bit.ly/M6tw4D WebAIM JAWS Shortcuts http://bit.ly/M6sBRM
  63. 63. Community & Blogs @webaim @paciellogroup @stevefaulkner @dequesystems ! www.webaim.org www.a11yproject.com www.accessibleculture.org www.webaxe.org www.simplyaccessible.com/archives ! an `a11y` meetup near you! http://bit.ly/1bhN3dW

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