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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
