accessibility and the web lecturer: judy kay references: readings - w3c - checklist of checkpoints...

Accessibility and the web

Lecturer: Judy Kay

References:Readings - W3C - Checklist of Checkpoints for Web Content Accessibility Guidelines 1.0

http://www.w3.org/TR/WAI-WEBCONTENT/

Overview

• What is accessibility?

• Why you want to know about accessibility?

• W3C-WAI – Guidelines– Standards and conformance

• Automation

• Case studies

What is accessibility?

"The power of the Web is in its universality. Access by everyone regardless

of disability is an essential aspect." Tim Berners-Lee ,

W3C Director and Inventor of the World Wide Web

http://www.w3.org/WAI/wcag-curric/int2-0.htm

Usability is the extent to which

a product can be used by specified

users to achieve specified goals with

effectiveness, efficiency and satisfaction

in a specified context of use.

– Definition from ISO 9241-11

What is accessibility?

• Enabling web access to people with disabilities…

• Web sites design so that people with disabilities can use them effectively

• Browsers and media players • Mesh with assistive technologies• Authoring tools to produce accessible content

and for use by people with disabilities

URL: http://www.nathan.com/Blooper Category: navigation, accessibility, legibility 2001

http://deyalexander.com/blooper/report.php?id=20

Note: text small - hard for all to read and, next slide is what visuallyImpaired users get

URL: http://www.melbfoodwinefest.com.au/Blooper Category: accessibility, browser compatibility 2002

http://deyalexander.com/blooper/report.php?id=125

Looks ok?

What is delivered to blind user?

Fix: remove vacuous tags on layout images

URL: http://www.buddyleeattractions.com/Blooper Category: navigation, accessibility Date: 19 April 2002

http://deyalexander.com/blooper/report.php?id=149

Navigation linksMove across screen!

Vision impaired users?Physically impaired?

Nature of disabilities

• Vision, blindness … low vision– Problems with small visual elements

– Assistive technology reads site

• Hearing loss– Problems with audio elements

• Physical limitations– Challenges in keyboard input, assistive technology

• Cognitive and neurological

Nature of disabilities

• 10% of people with some disability eg colour blindness…

• Context-dependent ‘disability’– Noisy (audio)– Screen glare (visual)

Roles for the Web

• Digital libraries

• Entertainment

• News

• Government services

• Educational resources

The really good news?

• Good design helps everyone!

• Thinking about accessibility for those with handcaps…

• Makes for sites that are more accessible to others too

• Clarity over cuteness

Why you want to know about accessibility?

Why you want to know about accessibility?

• Important for millions of users with disabilities• Generally results in better overall design• Web is increasingly source of critical information

and services• Legal requirements• Financial merits

– For companies

– For you

Marketplace issues

• Disability is widespread already

• Aging population

• Potential legal costs

Overall approaches

• Good design for all• Text is king

– For assistive technologies– For search technologies

• Alternative modalities– image plus text– Audio + text caption

• Use of style sheets

W3C-WAI Guidelines

• 1. Provide equivalent alternatives to auditory and visual content.

• 2. Don't rely on color alone. • 3. Use markup and style sheets and do so

properly. • 4. Clarify natural language usage • 5. Create tables that transform gracefully. • 6. Ensure that pages featuring new

technologies transform gracefully.• 7. Ensure user control of time-sensitive

content changes.

W3C-WAI Guidelines

• 8. Ensure direct accessibility of embedded user interfaces.

• 9. Design for device-independence. • 10. Use interim solutions. • 11. Use W3C technologies and guidelines. • 12. Provide context and orientation

information. • 13. Provide clear navigation mechanisms. • 14. Ensure that documents are clear and

simple.

W3C-WAI

• Priorities– 1 must– 2 should– 3 may

Priority 1 guidelines

• 1.1 text equivalent of all visual elements• 2.1 support interpretation of colour with other

cues• 4.1 clearly indicate changes of natural language• 6.1 readable without style sheets• 6.2 update dynamic equivalent with content• 7.1 avoid flicker• 14.1 clear, simple language matching purpose

Non-text elements:• 1.1a - images and graphical buttons. • 1.1b - graphical representations of text• 1.1c - image map regions. • 1.1d - animations (e.g., animated GIFs). • 1.1e - applets and programmatic objects. • 1.1f - ASCII art. • 1.1g - a text equivalent for frames. • 1.1h - scripts• 1.1k-m - sounds, audio files (& in video)• 1.1n - a text equivalent for video.

W3C-WAI standards, conformance

• The principles (see readings)

• Apply them in your projects

• Use as one set of heuristics

• ExamplesFrom

http://www.w3.org/WAI/wcag-curric/sam1-0.htm

1.1 text equivalent of all visual elements

1.1a - text equivalent for images and graphical

buttons

• <IMG SRC="home.gif" ALT=" Drawing of a house .">

Where this is a decoration:

http://www.w3.org/WAI/wcag-curric/sam2-0.htm

1.1a - text equivalent for images and graphical

buttons

<A HREF="home.htm"> <IMG SRC="home.gif"

ALT="Link to the Home page."> </A>

Where this is a link:

1.1a - text equivalent for images and graphical

buttons

Need text form available by some means eg. Link to page with each element described

ALT is not enough:

http://www.w3.org/WAI/wcag-curric/sam3-0.htm

1.1d - text for animations (e.g., animated GIFs)

<IMG SRC="ani-bal.gif" ALT="An animated expanding and bursting balloon.">

http://www.w3.org/WAI/wcag-curric/sam7-0.htm

Explanation of animation:

1.1a - text equivalent for images and graphical

buttons

<IMG SRC="wai.gif" ALT="Web Accessibility Initiative">

Images with text within:

http://www.w3.org/WAI/wcag-curric/sam11-0.htm

4.1 clearly indicate changes of natural language

Mother, he's asking you to go. He's saying, "Allons, Madame plaisante!"

Coded as:

Mother, he's asking you to go. He's saying,<SPAN lang="fr"> "Allons, Madame plaisante!"</SPAN>

http://www.w3.org/WAI/wcag-curric/sam40-0.htm

7.1 avoid flicker

Flicker

• Can cause seizures for some people with epilepsy

• 4 - 59 Hz esp around 20 and esp changes between light and dard

• Beware in design of gifs and similar potential sources of flicker

• Movement is distracting for all - avoid it

Lower priority checkpointsEg 2.2

Ensure that foreground and background color combinations provide sufficient contrastwhen viewed by someone having color deficits or when viewed on a black and white screen.

http://www.w3.org/WAI/wcag-curric/sam26-0.htm

Discussion

• Better for all

• Why only Priority 2?– User has control of background at browser

W3C-WAI standards, conformance

• 1.1 Text equivalent for every non-text element– Images

– Graphical text

– ASCII art

– Images regions

– Animations

– Applets and other programmed elements….

• Use tags, alt, longdesc

Automation

• Ref:• http://www.w3.org/WAI/ER/existingtools.html

• Evaluation - a static analysis report/rating for accessibility.

• Repair tools - help author make problem pages more accessible.

• Filter and transform tools - assist Web users modify a page or supplement an assistive technology or browser.

The browser as a tool

• Change the font to a larger size• View pages without images• View pages with styles sheets and pages

colours/fonts disabled• View pages with an alternative, high contrast,

colour scheme• Use the keyboard not the mouse to navigate• Disable scripts, applets and/or plugins • Try different browsers & versions

Colour checking

Colour Contrasthttp://www.lighthouse.org/color_contrast.htm

Colour tester – colour blindhttp://www.vischeck.com/

Legible texthttp://www.lighthouse.org/print_leg.htm

Links

• Link checkers: non-existent URLs• http://www.linkalarm.com/

• http://www.tetranetsoftware.com/solutions/linkbot/looking-for-linkbot.asp

• http://www.cyberspyder.com/cslnkts1.html

• http://validator.w3.org/checklink

validators

• HTML Validator – Eg W3C: http://validator.w3.org/

• CSS Validator– W3C http://jigsaw.w3.org/css-validator/

• Commercialhttp://www.usablenet.com/https://www.cryptzone.com/products/content-

governance/compliance-sheriff/accessibility-compliance

Case study

• Australian University web sites

• Dey AlexanderUsability SpecialistIT Services DivisionMonash University

• dey.alexander@its.monash.edu.au

Challenges in accessibility

• Who creates web sites?• What is their expertise in accessibility?• The amateur factor

• Study of 4 main pages of 45 universities WCAG 1.0 - 14 broad guidelines and 65 checkpoints

Following pages from Dey’s online presentation

http://deyalexander.com/presentations/accessibility-universities/

Methodology

1. Pages viewed in IE 6• Screen was captured• Source was saved

2. Pages then viewed in IE 6 with stylesheet support turned off

3. Pages then viewed using Delorie’s Web Page Backward Compatibility Viewer

• Once with stylesheet support turned off (simulates older GUI browsers)

• Once with scripting support turned off

Methodology (cont.)

4. Pages were viewed in Lynx 2.8.45. Screen capture of pages was taken with Delorie’s

Lynx Viewer6. Pages were then checked with Webaim’s The

Wave

All pages were evaluated Jan 27 - Feb 15, 2003So it is ok to share them now….

Research findings

• 98% (ie all but one) of Australian university sites failed to meet all priority 1 WCAG 1.0 checkpoints

• 153 of the 180 pages failed on at least 1 checkpoint• Most failures were against checkpoint 1.1 –

requirement to provide a text equivalent for non-text elements– 138 page failures (across 98% of sites)– Most of these (133 pages, 95.5% of sites) related to text

equivalents for images

Image-related checkpoint 1.1 failures

• Seven types of problems were found (5 of these were recorded as checkpoint failures)1. Text alternatives were not equivalent2. Text alternative included unnecessary data3. No text alternative – blank “alt” attribute4. No Text alternative – no “alt” attribute5. Background images with content6. Decorative/layout images with unnecessary data 7. Decorative/layout images with no “alt” attribute

1. Text alternative not “equivalent”

<img alt=“Orientation Week”> – no date given

<img alt=“Apply online”> – no context (on or off campus) given

41 pages

1. Text alternative not “equivalent”

<img alt=“Staff directory”> – no indication of restricted access was provided

<img alt=“News”> – no story details were given

1. Text alternative not “equivalent”

<img alt=“ACU locations”> – as though the purpose of “alt” was for meta data (info about the image, rather than an equivalent)

<img alt=“Location guide and Bond scenes ”> – again, an apparent usage of alt=meta data

2. Text alternative includes unnecessary data

Image sliced in three – to align with three navigation rows. Each slice has text alt of“University of Western Australia”

Many images have text alt “Link to…”

21 pages

3. No text alternative – blank “alt” attribute

Link to enrolment information, but <img alt=“”> – no information provided

Link to Orientation information, but <img alt=“”> – no information provided

11 pages

4. No text alternative – no “alt” attribute

All images on this site: <img src=“filename.gif”> – no “alt” attribute

65 pages

5. Background image with content

1 page

6. Layout image with unnecessary data

53 pages

<img alt=“desert sand”> - not necessary and potentially confusing

Adding text alternativesto spacer images can resultin annoying repetition ofuseless information

7. Layout image with no “alt” attribute

• Most common error of all89

pages

<img src=“spacer.gif”>

vs

<img src=“spacer.gif” alt=“”>

Conclusions

• Results indicate that our sites are likely to present significant accessibility problems for some users

• University web authors—including specialist web teams—do not appear to have an acceptable understanding of accessible web design techniques

• QA processes are either– Not being adhered to

– Don’t include accessibility components

Acknowledgements on tools:

• Online presentations and sites:

• OZWAI site– Jason White – Co-Chair, Web Content

Accessibility Guidelines Working Group– Naomi Heagney – The Hiser Group– Andrew Arch – Vision Australia Foundation