Web Accessibility What is it? Why is it important? Sharon Trerise Coordinator of Accessible IT...
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Transcript of Web Accessibility What is it? Why is it important? Sharon Trerise Coordinator of Accessible IT...
Web AccessibilityWhat is it?
Why is it important?
Sharon TreriseCoordinator of Accessible ITNortheast ADA & IT Center
Employment and Disability Institute www.edi.cornell.edu
Resources
• AccessIT (National Center on Accessible Information Technology in Education)– www.washington.edu/accessit
• ITTATC (Information Technology Technical Assistance and Training Center)– www.ittatc.org
• WebAIM (Web Accessibility in Mind)– www.webaim.org
Topics
• What is an accessible web page?
• What does accessibility mean to a person with a disability?
• Why should you care?
Who defines accessibility?
• World Wide Web Consortium– Web Content Accessibility Guidelines (WCAG)
version 1 (current) & version 2 (draft)– 14 Guidelines: Priority Levels 1, 2 & 3
(1: must do, 2: should do, 3: may do to improve accessibility)
• Federal Government– Section 508 of the Rehabilitation Act - § 1194.22
Web-based intranet and internet information and applications
– 16 Standards
Who defines accessibility?
• New York State– New York State's Official Policy/Standards
"Accessibility of State Agency Web-based Intranet and Internet Information and Applications"
• NYS Statewide Technology Policy P04-002http://www.oft.state.ny.us/policy/p04-002/index.htm
• NYS Mandatory Technology Standard S04-001http://www.oft.state.ny.us/policy/s04-001/index.htm
What does an accessible web page mean to a person with a disability?
• People who are blind or visually impaired• People who are color blind• People who are deaf or hearing impaired• People with mobility impairments• People with cognitive impairments
People who are blind
• Do not use a mouse• May use a screen
reader to listen to the content
• May use a refreshable Braille display
All content must be accessible from the keyboard only
Images, photos and graphics are unusable
Colors are unusable
Navigation may be difficult / confusing
Blindness: Accessible Design Techniques
• Provide text description for all images & photos (“alt” attribute / alt text)
• Provide an option to skip navigation• Ensure keyboard accessibility• Use meaningful links (“Class schedule” rather than
“click here”)• Use proper HTML (header tags, etc.) *Ins F6
• Don’t write scripts that require mouse usage• Do not rely on color alone to convey important
information
WCAG 1.1: Text Equivalents (Priority 1)
• Provide a text equivalent for every non-text element (e.g. via “alt”, “longdesc” or in element content).
•Images•Graphical representations of text•Image map regions•Animations•Applets & programmatic objects•Frames
•Scripts•Images used as bullets•Spacers•Graphical buttons•Sounds•Audio files•Audio tracks of video
WCAG 2.1: Use of Color (Priority 1)
• Ensure that all information conveyed with color is also available without color, for example from context or markup
WCAG 8.1: Scripts & applets (Priority 1)
• Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies
WCAG 3.5: Document Structure (Priority 2)
• Use header elements to convey document structure and use them according to specification
People with Low Vision
• May use screen magnification software
Images, photos and graphics may become unusable when enlarged
Navigation may be difficult / confusing
Low Vision: Simulation
• Magnification– Accessible example
– Less accessible example
• IE v. 6.0– Enlarge fonts
Low Vision: Accessible Design Techniques
• Limit or eliminate text within graphics
• Have plenty of contrast• Use relative rather than
absolute font sizes
WCAG 2.2: Color contrast (Priority 2 & 3)
• Ensure that foreground & background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black & white screen
WCAG 3.4: Relative sizing (Priority 2)
• Use relative rather than absolute units in markup language attribute values and style sheet property values
Color Blindness
• Approximately 8-10% of the male population and about 0.5% of the female population experience some form of color
deficiency • May change color
settings in browser• Cell phone, PDA and text
browser users may not have color
Reds & greens are often indistinguishable
Other colors may be indistinguishable
Color Blindness: SimulationMap of Hurricane Isabel (with red/green colorblindness)
Simulated using Vischek (http://www.vischeck.com/vischeck/vischeckURL.php )
Color Blindness: Accessible Design Techniques
• Do not use color alone to convey content– Use additional cues or information to convey
content
The flights listed below in RED have been cancelled. The flights in GREEN are departing on time.
Delta 1342United 320American Airlines 787Southwest 2390
The flights listed below that have been cancelled are indicated in RED and by an asterisk. The flights in GREEN are departing on time.
Delta 1342*United 320American Airlines 787Southwest 2390*
WCAG 2.1: Use of Color (Priority 1)
• Ensure that all information conveyed with color is also available without color, for example from context or markup
People with mobility impairments
• May use only the keyboard for navigation
• May tire quickly• May not have fine
motor control
All content must be accessible from the keyboard
Lengthy navigation may cause fatigue
Small or moving links are difficult to select
Mobility Impairment: Simulation
Provide a way to skip over lengthy lists of navigation
• Inaccessible example• Accessible example
Ensure the page can be navigated using the keyboard only
• Inaccessible example
Mobility Impairments: Accessible Design Techniques
• Ensure that the page is keyboard accessible
• Do not require fine motor control (free of moving links or very small links)
• Provide a way to skip over long lists of links & other lengthy content (visible “skip to main content” link)
WCAG 6.3: Scripts & Applets (Priority 1)
• Ensure that pages are usable when scripts, applets and other programmatic objects are turned off or not supported. – If this is not possible, provide equivalent information on an
alternative accessible page.
WCAG 6.4: Device Independence (Priority 2)
• For scripts and applets, ensure that event handlers are input device-independent.
WCAG 7.3: Moving Content (Priority 2)
• Until user agents allow users to freeze moving content, avoid movement in pages.
Section 508, Standard (o): Skip navigation
• A method shall be provided that permits users to skip repetitive navigation links.
People who are deaf or hearing impaired
• Audio is unusable Video clips that include audio are unusable
Audio clips are unusable
Deafness: Accessible Design Techniques
• Provide transcripts for all audio content • Provide synchronized captions for all video
content• Many people benefit
– Students in library w/o headset– People with learning disabilities– People for whom English is not their primary
language– People in a noisy environment– Everyone (content is presented in >1 medium)
WCAG 1.4: (Priority 1)
• For any time-based multimedia presentation (e.g. movie or animation), synchronize equivalent alternatives (e.g. captions or auditory descriptions of the visual track) with the presentation
People with cognitive impairments
• Users may have difficulty focusing on or comprehending lengthy sections of text
• Complex layouts or inconsistent navigational schemes may be confusing
• May need content in >1 form
Animated images may be distracting
Complex layouts may lead to confusion
Text-only content may be limiting
Cognitive Impairment: Accessible Design Techniques
• Simplify the layout as much as possible• Provide clear and consistent site navigation• Organize information into manageable
“chunks”• Logically organize your site and individual
documents• Use icons, illustrations, arrows, audio, video or
other multimedia to enhance understanding
WCAG 14.1: Language (Priority 1)
• Use the clearest and simplest language appropriate for a site’s content.
WCAG 7.2: Use of Blinking (Priority 2)
• Until user agents allow users to control blinking, avoid causing content to blink
WCAG 12.3: Large block of text (Priority 2)
• Divide large blocks of information into more manageable groups where natural and appropriate
Why make your web pages accessible?
• Who does your audience consist of?– Students (current and prospective)– Faculty– Staff– Alumni– Parents– Community– World
EVERYONE
Disability as a Function of Age
7 9 15 2029
37
59
0
10
20
30
40
50
60
70
18-24 25-34 35-44 45-54 55-64 65-74 75+
Age
% of population with a disability
Source: U.S. Census Bureau Report on Americans with Disabilities: 1994-95, P70-61 (August 1997)Based on Survey of Income and Program Participation, Oct. 1994-Jan. 1995
Why make web pages accessible?
• Our aging population– In 2010, the majority of the US population
will be 45 years and older
Brian Basset, Cartoonist and creator of syndicated cartoon
Adam@Home
http://www.microsoft.com/enable/aging/default.aspx
Web Accessibility: Designing for Everyone
• People using different web browsers• People using different screen resolutions• People using phone web services• People using handheld display units• People using car computing systems• People using screen readers• People who are deaf or hard of hearing• People who can’t use a mouse• People who are color blind• People with differences in attention/perception