All change for WCAG 2.0

Patrick H. Lauke / Manchester Digital Development Agency / 24 March 2009

WHAT YOU NEED TO KNOW ABOUT THE NEW ACCESSIBILITY GUIDELINES

About me... Web Editor for University of Salford Web Standards Project (WaSP) Author and occasional .net

magazine contributor NOT an expert?

Outline Background on WCAG 1.0 The painful birth of WCAG 2.0 Overview of the new guidelines Next steps for WCAG 1.0 veterans

Web Content Accessibility Guidelines 1.0

www.w3.org/TR/WCAG10 W3C recommendation 5 May 1999 14 guidelines 75 checkpoints

WCAG 1.0 – problems HTML-centric checkpoints, despite

separate techniques document http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/

“until user agents” clauses Forbids JavaScript and any non-W3C

technologies Vague checkpoints

WCAG 2.0 – early attempts Work began soon after release of

WCAG 1.0 Many iterations, largely under radar

of web devs Original “Last Call” April 2006

To Hell with WCAG 2.0 Joe Clark's vitriolic style A List Apart, 23 May 2006

http://www.alistapart.com/articles/tohellwithwcag2

Main points of concern: Overall size of combined

guidelines Inscrutable language Baseline concept Omission of markup validation /

standards

To Hell with WCAG 2.0 Generated huge interest from web

devs Joe Clark started WCAG Samurai

project to create errata for WCAG 1.0 W3C demoted WCAG 2.0 from Last

Call back to Public Working Draft

WCAG 2.0 back on track Joe Clark's leaving speech at

@media2007 – confident that WCAG 2.0 heading in right direction

Historical aside: my take on amended WCAG 2.0 http://www.webstandards.org/2007/06/11/review-wcag2-may2007-working-draft/

Nonetheless released WCAG Samurai Errata http://wcagsamurai.org/

Web Content Accessibility Guidelines 2.0

www.w3.org/TR/WCAG20 W3C recommendation 11 December

2008

WCAG 2.0 suite of documents

WCAG 2.0 suite of documents Web Content Accessibility Guidelines

2.0 [normative] How to Meet WCAG 2.0 [informative] Understanding WCAG 2.0

[informative] Techniques for WCAG 2.0

[informative] http://www.w3.org/WAI/intro/wcag20

Web Content Accessibility Guidelines 2.0

4 general principles 12 guidelines 61 success criteria

WCAG 2.0 principles

A website should be...

Perceivable Operable Usable Robust

WCAG 2.0 improvements Principles, guidelines and success

criteria are technology-agnostic

WCAG 1.0 examples “Guideline 5. Create tables that

transform gracefully” “5.3 Do not use tables for layout

unless the table makes sense when linearized.”

“Note. Once user agents support style sheet positioning, tables should not be used for layout.”

So what happens with CSS positioning that breaks linear flow?

WCAG 2.0 examples “Guideline 1.3 Adaptable: Create content that

can be presented in different ways (for example simpler layout) without losing information or structure.”

“1.3.2 Meaningful Sequence: When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.”

WCAG 2.0 improvements WCAG 1.0 “Guideline 11. Use W3C

technologies and guidelines” “Where it is not possible to use a W3C

technology, or doing so results in material that does not transform gracefully, provide an alternative version of the content that is accessible.”

WCAG 2.0 can be applied to W3C and non-W3C technologies (as long as they're accessibility-supported)

WCAG 2.0 improvements Accessibility-supported

technologies supported by users' assistive

technology technology must have

accessibility-supported user agents that are available to users

WCAG 2.0 accessibility-supported You can use PDF, Flash, even

JavaScript JavaScript and WAI-ARIA

http://www.w3.org/TR/wai-aria/ Even if a technology isn't fully

accessibility-supported, as long as you use the supported bits

Worst case provide fallback that is supported

WCAG 2.0 improvements Removes all “until user agents...”

clauses

WCAG 1.0 example “Guideline 10. Use interim solutions.” “10.4 Until user agents handle empty controls

correctly, include default, place-holding characters in edit boxes and text areas.”

WCAG 2.0 improvements Each success criterion is more easily

testable Success criteria give clearer

guidance than WCAG 1.0 checkpoints

WCAG 1.0 example “Guideline 2. Don't rely on color

alone.” “2.2 Ensure that foreground and

background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen.”

What exactly is “sufficient”?

WCAG 2.0 example “Guideline 1.4 Distinguishable: Make it easier for users to

see and hear content including separating foreground from background.”

AA “1.4.3 Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1”

“Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1”

AAA “1.4.6 Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1”

“Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 4.5:1”

WCAG 2.0 improvements As a result of clearer, testable SCs

some things are allowed that previously weren't

WCAG 1.0 example “Guideline 7. Ensure user control of

time-sensitive content changes.” “7.1 Until user agents allow users to control

flickering, avoid causing the screen to flicker.”

“7.2 Until user agents allow users to control blinking, avoid causing content to blink[...]”

WCAG 2.0 example “Guideline 2.3 Seizures: Do not design

content in a way that is known to cause seizures”

“2.3.1 Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.”

WCAG 2.0 improvements Success criteria focus on the

outcomes, not how they're achieved

WCAG 1.0 example “Guideline 9. Design for device-

independence.” “9.5 Provide keyboard shortcuts to

important links (including those in client-side image maps), form controls, and groups of form controls.”

“For example, in HTML, specify shortcuts via the "accesskey" attribute.”

WCAG 2.0 example “Guideline 2.1 Keyboard Accessible:

Make all functionality available from a keyboard.“

“2.1.1 Keyboard: All functionality of the content is operable through a keyboard interface [...]”

WCAG 2.0 improvements Talks about mechanisms “process or technique for achieving a

result”

WCAG 2.0 mechanism example “Guideline 2.4 Navigable: Provide ways to help

users navigate, find content, and determine where they are.”

“2.4.1 Bypass Blocks: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages.”

Does this mandate skip links?

WCAG 2.0 mechanism example Looking at “How to meet WCAG 2.0”,

skip links only one of a few techniques mentioned

Sufficient Techniques for 2.4.1 - Bypass Blocks: Creating links to skip blocks of repeated

material Grouping blocks of repeated material in a

way that can be skipped Advisory Techniques for 2.4.1 - Bypass Blocks

[…] C6: Positioning content based on structural

markup

WCAG 2.0 techniques Techniques cover general

technologies: HTML, CSS, JavaScript, WAI-ARIA

Sufficient and advisory techniques Techniques are informative, not

normative List of techniques is not exhaustive –

invent your own as long as success criteria are fulfilled

WCAG 2.0 conformance WCAG 1.0 had duality of priority

1,2,3 that mapped to levels A, AA, AAA

WCAG 2.0 just uses A, AA, AAA model for both SCs and conformance levels

WCAG 2.0 conformance Applies to full pages Complete processes Only accessibility-supported techs are

relied on Non-interference (when adding non-

accessibility-supported technologies) You can conform without a

conformance claim

WCAG 2.0 partial conformance 3rd party content (UGC, feeds, etc) Use of languages/technologies without

accessibility-support (future-proofing?)

Transition from WCAG 1.0 to WCAG 2.0

Needs of users with disabilities hasn't changed

Technology that they use has If your site accessible under WCAG

1.0, shouldn't be too far off WCAG 2.0

Transition from WCAG 1.0 to WCAG 2.0

How WCAG 1.0 differs from WCAG 2.0 http://www.w3.org/WAI/WCAG20/from10/diff.php

Comparison WCAG 1.0 checkpoints to WCAG 2.0 http://www.w3.org/WAI/WCAG20/from10/comparison/

How to update your site from WCAG 1.0 to 2.0 http://www.w3.org/WAI/WCAG20/from10/websites.html

Transition from WCAG 1.0 to WCAG 2.0

Evaluate your site based on WCAG 2.0 SCs

Many 1.0 checkpoints map to 2.0 SCs

Are there 1.0 requirements that have been lifted?

Test more specific 2.0 SCs

Getting started with WCAG 2.0 WebAIM's unofficial checklist

http://webaim.org/standards/wcag/checklist

Getting started with WCAG 2.0 For a “one-stop shop” overview,

customisable WCAG 2.0 quick reference http://www.w3.org/WAI/WCAG20/quickref/

Recap on WCAG 2.0 Technology-agnostic – applicable to

more present and future technologies Clearly testable Success Criteria Focussed on outcome for users, not

techniques Removes outdated requirements

from 1.0 Overall allows authors more freedom

Thanks

Patrick H. Laukehttp://www.splintered.co.uk