ECA 228 Internet/Intranet Design I Accessibility.

ECA 228 Internet/Intranet Design I

Accessibility


accessibility issues

some users– can’t see, hear, or move the way we do – may not mentally process information easily– may have difficulty reading – may not be able to use keyboard or mouse – may have a text-only screen, or very small screen – may have a voice browser


accessibility issues cont …

making your site accessible to users with disabilities may benefit all users– EG, your choice to use stylesheets to control

style across your site may benefit a user with low vision, but may actually decrease download time for all users

by law, some sites must be accessible to more than just sighted, hearing users


Web Accessibility Initiative

WAI attempts to make the web more accessible to everyone

5 primary areas1. Technology

2. Guidelines

3. Tools

4. Education and Outreach

5. Research and Development


guidelines

Guidelines address 2 general themes: Graceful Transformation

– separate structure from presentation– provide text alternatives, such as the alt attribute in

<img> tags– create documents that work even if users cannot

see or hear – include information that serves the same purpose as audio or video

– create documents that do not rely on one type of hardware, eg, large monitors


guidelines cont …

Making Content Understandable and Navigable– make language clear and simple– provide understandable mechanisms for navigating

through site– some users cannot use image maps, frames,

graphics– some users may lose contextual information when

they can view only a portion of the page put important information above fold eg, magnified images only display one word at a time Braille readers


guidelines cont …

checkpoints– each guideline may contain one or more

checkpoints explanations of how the guideline applies in real-world

scenario

– each checkpoint is assigned a priority level


priority levels

Level 1– site must satisfy this checkpoint, otherwise it will be

impossible for some groups to access information

Level 2– site should satisfy this checkpoint – significant

barriers may be removed

Level3– site may address this checkpoint – will improve

overall accessibility


conformance

A document may be rated on its compliance to the 3 priority levels

3 levels of conformance standards1. LEVEL A: all Priority 1 checkpoints are satisfied

2. LEVEL Double-A: all Priority 1 and 2 checkpoints are satisfied

3. LEVEL Triple_A: all Priority 1, 2, and 3 checkpoints are satisfied

Know Your Audience


Guideline 1

– if a user cannot use images, movies, sounds, etc, provide equivalent information

– guidelines do not suggest avoiding using the above, but providing a text equivalent

– text equivalents may be used as synthesized speech, Braille, visually displayed text

Provide equivalent alternatives to auditory and visual content.


Guideline 1 cont …

– text equivalent must serve the same function or purpose as an image

– EG, the purpose of image of earth from outer space decoration

alt = “photograph of earth from outer space” illustration of world geography

alt = “the polar caps can clearly be seen from outer space” link to information about the earth

alt = “click this link for more information about the earth”



– if the text conveys the same purpose for a user with a disability as the image does for other users, it can be considered equivalent

– consider using non-text equivalents (pictures, video, audio) for users who have difficulty reading

– Checkpoints: Provide text equivalent for every non-text element,

including images, applets, ascii art, animations, buttons, image map regions, etc


Guideline 2

– ensure that that text and graphics are understandable when viewed without color

– foreground and background should not be too close to the same hue

– some users may not be able to differentiate colors– Checkpoints:

Make sure any information conveyed with color is also conveyed other ways as well

Don't rely on color alone.


Guideline 3

– markup documents with proper structural elements– control presentation with style sheets rather than

presentational elements <font>

– invalid HTML hinders accessibility– using a table to lay out a page may cause problems– do not use presentational markup to convey structure

Use markup and style sheets and do so properly.


Guideline 4

– identify predominant natural language of the document using meta tags

– Checkpoints: Identify changes in the natural language of a documents

text. EG, if you include a non-English word in an English document, identify the language with the lang attribute.

Clarify natural language usage.


Guideline 5

– tables should be used to mark up tabular data, not to lay out a page

– Checkpoints: For data tables having 2 or more logical levels of rows or

columns ( header cells, body, footer) use markup to designate those levels ( thead, tbody, tfoot )

Identify row and column headers

Create tables that transform gracefully.



– some screen readers reads table cells straight across

– will be read as

Abraham Lincoln's Gettysburg Address, delivered 19 November, 1863

Four score and seven years ago our fathers brought forth upon this continent a new nation …

Abraham Lincoln's Gettysburg Four score and seven years ago Address, delivered 19 November, our fathers brought forth upon 1863 this continent a new nation …


Guideline 6

– ensure that pages are accessible even when newer technologies are not supported or are turned off

– Checkpoints: Organize the structure of your document so that it still

makes sense even if style sheets are not working as you expect

Ensure that pages are usable even when scripts, applets, and other objects are turned off

Ensure that pages featuring new technologies transform gracefully.


Guideline 7

– ensure that moving, blinking, scrolling, or auto-updating objects or pages may be paused or stopped

– Checkpoints: Avoid causing the screen to flicker – some people with

epilepsy can have seizures triggered by flickering or flashing in the 4 to 59 flashes per second range

Ensure user control of time-sensitive content changes.


Guideline 8

– when you have an embedded object that has its own interface, make sure that interface as well is accessible

– Checkpoints: Make programmatic elements such as scripts and applets

compatible with assistive technologies

Ensure direct accessibility of embedded user interfaces.


Guideline 9

– use features that enable activation of page elements via a variety of input devices

– don’t rely only on one device (mouse, keyboard, etc) to navigate through site

– Checkpoints: Provide client-side image maps rather than server-side

image maps

Design for device-independence.


Guideline 10

– Use interim accessibility solutions so that assistive technologies and older browsers will operate correctly

– interim means that the W3 considers these issues at the moment, but expect these will not be a problem in the future, when web technologies come out with certain anticipated features

Use interim solutions.


Guideline 11

– use W3C technologies (according to specification) and follow accessibility guidelines

– W3C technologies include built-in accessibility features– avoid non-W3C and non-standard features ( proprietary

code )

Use W3C technologies and guidelines.


Guideline 12

– group elements and provide contextual information about the relationship between elements

– complex relationships between parts of a page may be difficult for people with disabilities to interpret

– Checkpoints: Title each frame to facilitate identification and navigation

Provide context and orientation information.


Guideline 13

– provide clear and consistent navigation mechanisms to increase the likelihood that a person will find what they are looking for at a site

orientation information navigation bars site map

Provide clear navigation mechanisms.


Guideline 14

– ensure that documents are clear and simple so they may be more easily understood

– consistent page layout, recognizable graphics, and easy to understand language benefits all users

– Checkpoints: Use the clearest and simplest language appropriate for a

site’s content

Ensure that documents are clear and simple.


validation

to check for accessibility, use:– automated tools– human review

invite individuals with disabilities to review the document invite both experienced and novice users get feedback from users with a wide range of disabilities

– hearing impaired– visually impaired– motor impairments


validation methods

use automated validation tools validate syntax of HTML validate style sheets view document in text-only browser view document in several browsers, old and

new view document in screen reader, with

magnification, on a small display, etc


validation methods cont …

use spelling and grammar checking– speech synthesizers may not be able to decipher

misspelled words– grammar problems may make document

incomprehensible

review the document for clarity and simplicity– ask a human editor to review document– identify cultural barriers


Bobby

http://bobby.watchfire.com comprehensive web accessibility software tool

– identifies barriers to accessibility

enter a url to check one page at a time– generates a report listing violations of Priority 1, 2,

and 3 issues– generates a list of user checks

Bobby is available for purchase

Date post:	27-Dec-2015
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ECA 228 Internet/Intranet Design I Accessibility.

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