The document summarizes a presentation given by Adrian Roselli on fringe accessibility techniques that should be avoided. It discusses common techniques like clicking on labels and checking color contrast. It then covers more fringe techniques such as avoiding default focus styles, using <h1> headings wisely, and setting the lang attribute. The document warns against disabling zoom, using tabindex greater than 0, and avoiding infinite scroll. It emphasizes that accessibility is an ongoing process rather than a checklist.
Developer Data Modeling Mistakes: From Postgres to NoSQL
Fringe Accessibility — Portland UX
1. Fringe Accessibility Techniques
(That Probably Shouldn’t Be)
Presented by Adrian Roselli for Portland Accessibility and User Experience Meetup
Slides from this talk will be available at rosel.li/pdxux
2. • I’ve written some stuff,
• Member of W3C,
• Building for the web since
1993,
• Learn more at
AdrianRoselli.com,
• Avoid on Twitter
@aardrian.
About Adrian Roselli
3. What We’ll Cover
• Common(?) Techniques
• The (not really) Fringe
• Key Takeaways
Work with me, people.
6. Common(?) Techniques
• Click on field labels
• Unplug your mouse
Make sure you can still use the page / application.
7. Common(?) Techniques
• Click on field labels
• Unplug your mouse
• Turn off images
Make sure no important content has disappeared.
8. Common(?) Techniques
• Click on field labels
• Unplug your mouse
• Turn off images
• Turn off CSS
Make sure the page still makes sense.
9. Common(?) Techniques
• Click on field labels
• Unplug your mouse
• Turn off images
• Turn off CSS
• Check color contrast
Make sure it’s sufficient.
10. Common(?) Techniques
• Click on field labels
• Unplug your mouse
• Turn off images
• Turn off CSS
• Check color contrast
• Consider hyperlink text
Be consistent and clear, managing expectations the whole time.
14. Use Link Underlines
• You are not Google:
• Users know Google’s layout,
• Users probably don’t visit your site daily.
• Relying on color alone will not suffice (WCAG 1.4.1 [A], 1.4.3 [AA]),
• Necessary contrast values:
• 4.5:1 between text and its background for copy,
• 3:1 between text and its background for larger text,
• 3:1 between surrounding text and a hyperlink, plus an additional visual cue
(G183).
http://adrianroselli.com/2014/03/i-dont-care-what-google-did-just-keep.html
http://adrianroselli.com/2016/06/on-link-underlines.html
16. Use :focus Styles
• Particularly if you removed link underlines,
• Everywhere you have :hover, add :focus,
• Look for :focus{outline:none;} in libraries:
• If you find it, remove it.
• Easy to test with the tab key.
http://adrianroselli.com/2014/06/keep-focus-outline.html
20. Avoid Default Focus Styles
• Edge and Firefox use dotted lines,
• WebKit browsers use blue line,
• WebKit browsers do not scale the style with the page,
• There is no guarantee they will be visible on all backgrounds,
• Consider WCAG 2.4.7 Focus Visible.
http://adrianroselli.com/2017/02/avoid-default-browser-focus-styles.html
22. Use <h#> Wisely
• Use only one <h1> per page,
• Don’t skip heading levels,
• Use appropriate nesting,
• There is no Document Outline Algorithm:
• Don’t use <h1> within every new <section> nor <article>,
• Multiple <h1>s will not help your SEO.
http://adrianroselli.com/2013/12/the-truth-about-truth-about-multiple-h1.html
http://adrianroselli.com/2016/08/there-is-no-document-outline-algorithm.html
23. Use Only One <main> per Page
Modified version of Hixie’s image at https://github.com/whatwg/html/issues/100#issuecomment-138620240
24. Use Only One <main> per Page
• <main> maps directly to role="main",
• AT users expect one main content block, may miss subsequent
<main>s,
• AT doesn’t expose that there are multiples,
• Can erode trust in landmark navigation.
http://adrianroselli.com/2015/09/use-only-one-main-on-a-page.html
25. Don’t Use tabindex > 0
https://www.digitalgov.gov/2014/11/17/user-experience-impossible-the-line-between-accessibility-and-usability/
26. Don’t Use tabindex > 0
https://www.digitalgov.gov/2014/11/17/user-experience-impossible-the-line-between-accessibility-and-usability/
27. Don’t Use tabindex > 0
• tabindex="-1"
• Use to set focus with script,
• Does not put it in tab order of page.
• tabindex="0"
• Allows user to set focus (e.g.: via keyboard),
• Puts in tab order of page (based on DOM).
• tabindex="1" (or greater)
• Do not do this,
• Messes with natural tab order.
http://adrianroselli.com/2014/11/dont-use-tabindex-greater-than-0.html
29. Maybe Use tabindex=0
• Do you have scrolling content boxes?
• Keyboard users probably cannot access it.
• Do you have content that expands on hover?
• Keyboard users probably cannot access it.
• A technique (for large, important blocks):
• <div role="region" aria-label="[if appropriate]"|aria-
labelledby="[if appropriate]" tabindex="0">
http://adrianroselli.com/2016/02/keyboard-and-overflow.html
30. <button>, <input>, or <a>
http://adrianroselli.com/2016/01/links-buttons-submits-and-divs-oh-hell.html
31. <button>, <input>, or <a>
http://adrianroselli.com/2016/01/links-buttons-submits-and-divs-oh-hell.html
32. <button>, <input>, or <a>
• Don’t use a <div> nor <span>.
• Does the control take me to another URL?
• Use an <a href>.
• Note: does not fire on space-bar.
• Does the control change something on the current page?
• Use a <button>.
• Does the control submit form fields?
• Use an <input type="submit"> or <button type="submit">.
http://adrianroselli.com/2016/01/links-buttons-submits-and-divs-oh-hell.html
35. Be Wary of Nesting Roles
• Just as you do not put <a href> in <button>,
• Do not nest an interactive control in another,
• Pay attention to polyfills, libraries that turn <div>s into
buttons via ARIA,
• Or ones that use tabindex.
http://adrianroselli.com/2016/12/be-wary-of-nesting-roles.html
40. Don’t Disable Zoom
• Allow users on mobile to zoom in,
• Look in <meta name="viewport"> for this:
• minimum-scale=1.0
• maximum-scale=1.0
• user-scalable=no
• Look in @-ms-viewport {} for this:
• zoom:1.0
• Grab your boss/client, shout “Enhance!”
http://adrianroselli.com/2015/10/dont-disable-zoom.html
42. Use Captions/Subtitles
• Everybody uses them:
• Working in public, in bed, at home,
• Surfing in public, in bed, at work.
• Should include audio descriptions,
• Should include speaker identification,
• Review auto-captions (“craptions”):
• NoMoreCraptions.com
http://adrianroselli.com/2013/11/captions-in-everyday-use.html
43. Use Captions/Subtitles
• Do video/audio clips have text alternatives?
• Are links to closed-captions or transcripts built into the player or
separate text links?
• Is there an audio description available?
• Tools:
• Media Access Australia YouTube captioning tutorial, Vimeo captioning
tutorial,
• Tiffany Brown’s WebVTT tutorial,
• DIY Resources for Closed Captioning and Transcription from 3 Play Media.
http://webaim.org/techniques/captions/
44. Test in Windows High Contrast Mode
http://buffalosoccerclub.org/About
45. Test in Windows High Contrast Mode
• It removes CSS background images,
• This has changed in Edge 14 / Win10 Anniv. Update,
• about:flags > Render backgrounds in high contrast
• Colors defined in your CSS are overridden,
• To activate:
• Left ALT + left SHIFT + PRINT SCREEN
• Media queries:
• -ms-high-contrast: active
• -ms-high-contrast: black-on-white
• -ms-high-contrast: white-on-black
http://adrianroselli.com/2012/08/css-background-images-high-contrast-mode.html
47. Avoid Infinite Scroll
• Makes it impossible to access some content:
• Footer,
• Sidebar links.
• Destroys the back button,
• Makes it impossible to share a URL to specific “page” of results,
• Makes it impossible to jump ahead several “pages” of results,
• Can overwhelm AT users, less powerful devices.
http://adrianroselli.com/2014/05/so-you-think-you-built-good-infinite.html
http://adrianroselli.com/2015/05/for-infinite-scroll-bounce-rate-is.html
49. Reconsider Typefaces for Dyslexia
• Use good typography rules:
• Avoid justified text,
• Use generous line spacing / leading,
• Use generous letter spacing,
• Avoid italics,
• Generally use sans serif faces,
• Use larger text,
• Use good contrast,
• Use clear, concise writing.
http://adrianroselli.com/2015/03/typefaces-for-dyslexia.html
51. Use On-Page Descriptions
• Not just for longdesc or aria-describedat, but any long
description technique,
• Use an in-page anchor,
• Don’t link to another page without reason:
• Consider burden of loading a new page,
• Consider burden of re-loading original page.
• Based on results of latest WebAIM screen reader survey
results.
http://adrianroselli.com/2015/09/use-on-page-image-descriptions.html
52. Not All Screen Reader Users…
http://adrianroselli.com/2017/02/not-all-screen-reader-users-are-blind.html
53. Not All Screen Reader Users…
http://adrianroselli.com/2017/02/not-all-screen-reader-users-are-blind.html
• 2015 WebAIM survey, 64% identified as blind:
• Low vision users,
• Users with cognitive impairments.
• Risks:
• Oddly hidden content,
• Broken source order,
• Element mis-use,
• Tabindex mis-use,
• Third-party add-ons.
55. Source Order Matters
• CSS techniques allow visual order to break from DOM order:
• Floats,
• Absolute positioning,
• Flexbox (see 5.4.1 of ED for a11y note),
• Grid (read Rachel Andrew on subgrid).
• WCAG 1.3.2 and 2.4.3 describe meaningful sequence and tab
order matching visual flow,
• Different behavior among different browsers.
http://adrianroselli.com/2015/09/source-order-matters.html
http://200ok.nl/a11y-flexbox/
57. • The following override native semantics in the browser:
– display: block
– display: inline
– display: grid
– display: flex
– display: contents
• Nothing in the HTML / CSS specifications mandates this,
• Does not work in reverse:
– display: table
– display: table-cell
Beware Display Properties
61. Why display: contents Is More Dangerous
• Yanks an element from the accessibility tree,
• You cannot add it back to the accessibility tree with ARIA,
– You can give it an accessible name and properties,
– But these are not passed to screen readers,
• Browsers do not hand the information off,
• If used as a poor-dev’s CSS reset:
– Will hide elements from assistive technology,
– Will hide semantics from assistive technology.
62. Try Not to Tweet Pictures of Text
https://twitter.com/jmspool/status/546303256990076929
https://twitter.com/lukew/status/541986091960528896
https://twitter.com/altonbrown/status/653030164985708544
63. Try Not to Tweet Pictures of Text
https://twitter.com/aardrian/status/733023365729005568
64. Try Not to Tweet Pictures of Text
• Twitter has finally added alternative text,
• Must be using iOS/Android app, full web site, some third-party
apps (Easy Chirp),
• Maybe also make your own:
• Reply to own tweet with alternative text,
• Link to a tweet and provide alternative text,
• Link to long-form alternative text.
http://adrianroselli.com/2016/03/twitter-has-alt-text-with-some-caveats.html
66. Share a11y Experiences
• We’re all trying to do what we can,
• Don’t attack those who don’t know what they don’t know,
• Someone may find something you never considered,
• You may get feedback on something you never considered.
http://adrianroselli.com/2015/07/lets-share-more-accessibility-experiences.html
73. Fringe Accessibility Techniques
(That Probably Shouldn’t Be)
Presented by Adrian Roselli for Portland Accessibility and User Experience Meetup
Slides from this talk will be available at rosel.li/pdxux
Notas del editor
CSS as implemented in browsers today can remove semantics,
Conversely, you can not add it back with CSS
Using NVDA with Firefox
Hit T to get to the table
Using Ctrl + Alt + arrow keys to navigate the table
Announces column headings as I change columns
Tells me when at the edge