Transcript Visual impairment - UW Staff Web Server

Web Accessibility
Rick Ells
[email protected]
UW Computing & Communications
Disability Types
The major categories of disability types are:

Visual


Hearing


deafness
Motor


blindness, low vision, color-blindness
inability to use a mouse, slow response time, limited fine motor control
Cognitive

learning disabilities, distractibility, inability to remember or focus on large
amounts of information
From: Introduction to Web Accessibility
http://www.webaim.org/intro/
Who has disabilities?
 Visual impairment
16% (27.4 million) of working-age adults have a mild visual difficulty
or impairment, and
11% (18.5 million) of working-age adults have a severe visual
difficulty or impairment.
 Dexterity impairment
19% (31.7 million) of working-age adults have a mild dexterity
difficulty or impairment, and
7% (12.0 million) of working-age adults have a severe dexterity
difficulty or impairment.
 Hearing impairment
19% (32.0 million) of working-age adults have a mild hearing
difficulty or impairment, and
3% (4.3 million) of working-age adults have a severe hearing
difficulty or impairment.
From: The Wide Range of Abilities and Its Impact on Computer Technology - A
Research Study Commissioned by Microsoft Corporation and Conducted by
Forrester Research, Inc., in 2003 http://www.microsoft.com/enable/research/
Web accessibility and the law
 1973 – Rehabilitation Act
 Prohibits discrimination on the basis of handicap by employers
receiving federal contracts or in federally assisted programs
 1990 – Americans With Disabilities Act
 Prohibits discrimination on the basis of disability in employment,
by governmental agencies, and in public accommodations
 1998 – Section 508 of the Rehabilitation Act
 Requires Federal departments and agencies to take into
consideration accessibility when developing, procuring, or using
electronic and information technology
http://www.section508.gov/
 By 2001, all Federal Web sites complied with requirements
Washington State and the UW
 UW has long standing policy of providing
reasonable accommodation for the
handicapped
 2005 – Washington State Department of
Information Services sets guidelines based
on Section 508 for government and
educational Web sites
http://isb.wa.gov/tools/webguide/accessibility.
aspx
Technologies and Strategies
Assistive Technologies





Alternative keyboards or switches
Braille and refreshable braille
Scanning software
Screen magnifiers
Screen readers
Adaptive Strategies






Speech recognition
Speech synthesis
Tabbing through structural elements
Text browsers
Visual notification
Voice browsers
From: How People with Disabilities Use the Web
http://www.w3.org/WAI/EO/Drafts/PWD-Use-Web/#tools
Device independence
 The Goal: Access to a Unified Web from Any Device in
Any Context by Anyone
From: Device Independence
http://www.w3.org/2001/di/
Building in device independence
 Organize content in simple hierarchical structure
(XML)
 Easier for each device to receive, interpret, and display
 Separate presentation from content (CSS)
 Allows separate presentation instructions for different
devices
 Provide alternatives
 Example: Text descriptions of graphics
 Define associations
 Examples: Text with form fields, row and column labels
Creating and using accessible content
From: Essential Components of Web Accessibility
http://www.w3.org/WAI/intro/components.php
Guidelines and Standards
From: Essential Components of Web Accessibility
http://www.w3.org/WAI/intro/components.php
Basic accessible design






Keyboard navigable:
A person with poor sight, no sight, or limited dexterity cannot use
a mouse.
Standards-compliant:
Pages that adhere to standards are easier to design assistive
and adaptive client programs for.
Makes sense linearly:
Encountering a Web page with a voice browser is a linear
process, progressing through the content in sequence or
navigating by the structure of the content. A sighted person using
a graphic browser can take in two-dimensional spatial
arrangements of content and go directly to any visible part.
Provides Alternatives:
Provide alternative text for people who cannot see graphics.
Helps make connections:
When you can only hear a page, it can be hard to tell which text
goes with which form field or which row and column a table cell
is in. Simple labeling of text and form field pairs and of rows and
columns enables assistive and adaptive programs to correctly
present content relationships.
Has no surprises:
No sudden pop-up windows or pages that take the reader away
from the page they are reading. No links that cannot be tabbed to
or evoked by pressing the return key.
10 quick tips to make an
accessible Web site
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Images & animations: Use the alt attribute to describe the function of each visual.
Image maps. Use the client-side map and text for hotspots.
Multimedia. Provide captioning and transcripts of audio, and descriptions of video.
Hypertext links. Use text that makes sense when read out of context. For
example, avoid "click here."
Page organization. Use headings, lists, and consistent structure. Use CSS for
layout and style where possible.
Graphs & charts. Summarize or use the longdesc attribute.
Scripts, applets, & plug-ins. Provide alternative content in case active features
are inaccessible or unsupported.
Frames. Use the noframes element and meaningful titles.
Tables. Make line-by-line reading sensible. Summarize.
Check your work. Validate. Use tools, checklist, and guidelines at
http://www.w3.org/TR/WCAG
From Quick Tips to Make Accessible Web Sites
http://www.w3.org/WAI/References/QuickTips/Overview.php
Poor form
From: Creating accessible forms, WebAIM,
http://www.webaim.org/techniques/forms/
Good form
From: Creating accessible forms, WebAIM,
http://www.webaim.org/techniques/forms/
Caption videos
Is your Web page accessible?
1.
2.
3.
4.
Check for standards-based, validated coding
Evaluate keyboard navigability of the page
Evaluate coding and page design
Check for Section 508 compliance using
WebXact (formerly known as Bobby)
From: Accessibility Evaluation Procedure,
AccessibleWeb@U,
http://www.washington.edu/computing/accessible/accessibleweb/eval_proc.html
Accessibility evaluation checklist
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Are frames appropriately titled?
Are ALT tags present and sufficiently equivalent to the graphic content?
Are form elements explicitly associated with labels?
Is information in PDF available in other more accessible formats?
Are all links and navigational elements present and contextually appropriate via the
keyboard?
Does the site avoid conveying meaning with color alone?
Are data tables marked up as required?
Is multimedia content captioned (or if audio only, transcribed)?
Is flickering content avoided?
Is a skip navigation link present if needed?
Is the page functional when scripts are disabled?
Is the page functional when style sheets are disabled?
Does link text provide a reasonable description of the link target?
If a page requires a timed response, can users request more time?
From: Web Accessibility Rubric, Terry Thompson,
http://staff.washington.edu/tft/rubric.php
A flood of new technologies
Web application model
From: Ajax: A New Approach to Web Applications
http://www.adaptivepath.com/publications/essays/archives/000385.php
Dynamic content
From: Ajax: A New Approach to Web Applications
http://www.adaptivepath.com/publications/essays/archives/000385.php
The promise of better interaction
Accessible Web applications
 Section 508 Tutorial: Developing Accessible
Software
Demonstrating principles by developing a calculator
in Visual Basic
http://www.access-board.gov/sec508/softwaretutorial.htm
 Software Applications and Operating Systems
(1194.21)
Program features that must be contained in software
for the product to meet Section 508 standards.
http://www.accessboard.gov/sec508/guide/1194.21.htm
Dynamic content
 Accessible DHTML, Mozilla, accessible Web ap
methods supported by FireFox 1.5 and WindowEyes
5.5 http://www.mozilla.org/access/dhtml/
 DHTML Accessibility - Fixing the JavaScript
Accessibility Problem,
Rich Schwerdtfeger and Becky Gibson, IBM,
http://www.csun.edu/cod/conf/2005/proceedings/252
4.htm
 Client-side Scripting Techniques for WCAG 2.0,
W3C,
http://www.w3.org/TR/WCAG20-SCRIPT-TECHS/
Is accessible design worth it?
 The handicapped are a valued part of the UW community and
they are not going away.
 The UW has a national reputation of supporting and
accommodating the handicapped.
 Your peer developers are already working on this problem (lots of
opportunities for conferences and papers).
 The methods needed here are already common in other
application software.
 Doing it right could avoid future hassles for the UW.
 You, or someone you love, may need adaptive or assistive
technology someday.
 It’s the human thing to do.