Web Accessibility

1
Web Accessibility

• Bernie D. Davenport A. Craig Dixon
• September 26, 2007

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Web Accessibility Defined

• Web accessibility refers to making web resources
  utile for all users, regardless of disability.
• The cardinal rule of web accessibility is that
  all users must be able to use the parts of the
  site that are essential to its message and
  function.
• Making web sites accessible requires some
  knowledge of the various kinds of assistive
  technologies used by people with disabilities to
  access the Web.
• Making web sites accessible often has the
  beneficial side effect of adding ease of use or
  additional functionality for users without
  disabilities.

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Types of Disabilities

• Web Accessibility in Mind (WebAIM) defines five
  types of disabilities of which web designers
  should be cognizant.
• Visual
• Auditory
• Motor
• Cognitive
• Seizure

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Visual Disabilities

• Visual disabilities include blindness, low
  vision, and colorblindness.
• Low vision users may utilize screen magnifiers or
  high contrast color schemes in order to see the
  information on the page more clearly.
• Blind users may utilize screen reader
  technologies that audibly read the contents of
  the page to the user.
• Because some users may be colorblind, page
  designers should never use color alone to convey
  a piece of information.

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Auditory Disabilities

• Auditory disabilities include deafness and
  hardness of hearing.
• Audio content that is critical to the message or
  function of the web resource should be captioned
  or transcribed.
• Audio content should be clear and free from
  background noise so it can be easily perceived by
  users who are hard of hearing.

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Motor Disabilities

• Motor disabilities include limited range of
  motion, slowness of motor response, and lack of
  fine motor control. These disabilities may be the
  result of bone or neuromuscular diseases, broken
  bones, or amputation.
• Users with motor disabilities often find using
  the keyboard preferable to using the mouse. Care
  should be taken to ensure that all page functions
  can be performed independent of the users input
  device.
• Time-sensitive tasks should also be avoided. If
  time-sensitive tasks are necessary, the user must
  easily be able to request more time to complete
  the task.

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Cognitive Disabilities

• Cognitive disabilities include learning
  disabilities, high susceptibility to distraction,
  an inability to process large amounts of
  information, and short-term memory loss.
• Many of the design principles for dealing with
  cognitive disabilities overlap with general
  principles of good web design. For example,
  writing to the lowest reading level appropriate
  for the intended audience.
• Because a users reading level often affects the
  speed at which they can read and process
  information, scrolling or marquee text should be
  avoided. If scrolling or marquee text is used,
  mechanisms for controlling its speed should be
  utilized.
• Often, graphics, diagrams, tables, etc. are
  useful in addressing cognitive disabilities. Care
  must be taken to make these visual aides as
  simple and understandable as practical, and the
  designer must account for visually-impaired users
  when including these elements in the pages
  design.

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Seizure Disabilities

• Some people are subject to photoepileptic
  seizures when viewing content that flashes,
  strobes, flickers, or blinks at a certain
  frequency.
• Content that blinks or flashes can also be
  distracting, making it a potential problem for
  those with cognitive disabilities as well.
  Because of this, blinking or flashing content
  should be avoided.
• If the content cannot be avoided, the user must
  be warned in advance about the presence of
  blinking or flashing content and possibility of
  triggering a seizure.

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Accessibility Goals

• WebAIM further defines four accessibility goals
  for web content. These are referred to by the
  acronym POUR.
• Perceivable
• Operable
• Understandable
• Robust

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Perceivability

• Perceivability refers to the ability of a user to
  access critical content via one of the senses
  that he or she has sufficient use of.
• For blind users, this could be audio perception.
• For deaf users, this could be visual perception.
• For deaf-blind users, this could be tactile
  perception via a Braille output device.
• The most efficient way to achieve accessibility
  is to ensure that content is transformable from
  one form to another.
• Text is the most transformable medium.
• Content must be separated from presentation.

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Operability

• Operability refers to the ability of a user to
  locate and interact with the critical content of
  the page.
• Some disabilities render users unable to use a
  mouse. Others make it preferable for the user to
  use a keyboard. Keyboard accessibility is one of
  the most crucial concepts in web accessibility.
• Efficient navigation is also a part of
  operability. Users should be able to skip parts
  of the page that are not relevant to them.
• In this way, site indices and search functions
  are components of good operability.
• Proper heading structures and good organization
  of information and links is also important.

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Understandability

• Understandability refers to the user being able
  to process the content and respond accordingly.
• Use of appropriate reading level and use of
  supplemental charts, graphics, etc. are important
  aspects of understandability.
• Understandability is also important in complex,
  multi-step processes like filling out a form or
  placing an order.
• Consistent design can be a major boost to
  understandability. Users quickly learn where to
  find the elements of your site (navigation
  controls, branding information, etc.) and are
  able to focus their attention on the content
  itself.

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Robustness

• Robustness refers to the ability of the user to
  get a consistent experience from the web resource
  regardless of the technology used to access it.
• Designers should account for differences in
  operating systems, browsers, browser versions,
  and settings and ensure that the web resource
  behaves the same way in as many configurations as
  possible.
• Designers should only require users to download
  additional resources such as plug-ins when
  expressing the content in another way is not
  practical.
• The users connection speed plays a role in
  robustness as well. Tasks that require large
  downloads may be considered inaccessible for
  users that do not have broadband Internet
  connections.

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World Wide Web Consortium (WC3)

• Created in October 1994
• Mission to lead the World Wide Web to its
  full potential by developing common protocols
  that promote its evolution and ensure its
  interoperability.
• 450 member organizations worldwide
• Developed the Web Accessibility Initiative (WAI)
  team
• To promote a high degree of usability for people
  with disabilities.
• Developed Web Content Accessibility Guidelines

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W3C Guidelines

• Provides guidance on accessibility of Web sites
• Contain 14 Guidelines for accessibility design
• Provides Checkpoints for each Guideline
• Makes pages more accessible to all users

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Priorities and Conformance Levels

• Priorities are assigned to each Checkpoint
• Priority 1 developer must satisfy
• Priority 2 developer should satisfy
• Priority 3 developer may satisfy
• Conformance Levels
• Single-A Priority 1 accessible
• Double-A Priority 1 2 accessible
• Triple-A Priority 1,2, 3 accessible

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WC3 Guidelines

• Why?
• To remove barriers from Web sites that prevent
  people with disabilities from accessing Web based
  information
• To remove barriers in the user agents
• Browsers
• Multimedia players
• Assistive Technologies

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W3C GuidelinesCommon Web Page Problems

• Images without alternative text
• Image Maps or Hotspots without alternative text
• Misleading use of structural elements such as
  tables
• Uncaptioned Audio
• Un-described Video

• Lack of alternative information for users who
  cannot access frames or scripts
• Tables that are difficult to decipher when
  linearized
• Poor color contrasts and color choices

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W3C Guidelines

• The following section provides information
  concerning
• The 14 W3C Guidelines
• The Related Checkpoints
• Priority 1 P1 Required by Jan 1, 2004
• Priority 2 P2 Should Incorporate
• Priority 3 P3 May Incorporate

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W3C Guidelines

• Guideline 1 of 14
• Provide equivalent alternatives to auditory and
  visual content

• 1.1 P1 Provide a text equivalent for every
  non-text element.
• 1.2 P1 Provide redundant text links for each
  active region of a server-side image map.
• 1.3 P1 Provide an auditory description of the
  important information of a visual track.
• 1.4 P1 Synchronize alternatives of a visual
  track with the presentation.
• 1.5 P3 Provide redundant text links for each
  active region of a client-side image map.

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W3C Guidelines

• Guideline 2 of 14
• Dont rely on Color alone

• 2.1 P1 All information conveyed with color must
  also be available without color.
• 2.2 P2, P3 All foreground and background color
  combinations must provide sufficient contrast
  when viewed on a black and white screen.

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W3C Guidelines

• Guideline 3 of 14
• Use markup and style sheets and do so properly

• 3.1 P2 Use markup rather than images to convey
  information.
• 3.2 P2 Validate to published formal grammars.
• 3.3 P2 Use style sheets to control layout and
  presentation
• 3.4 P2 Use relative rather than absolute units.
• 3.5 P2 Use Header elements to convey document
  structure.
• 3.6 P2 Mark up lists and list items properly.
• 3.7 P2 Mark up quotations.

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W3C Guidelines

• Guideline 4 of 14
• Clarify natural language used

• 4.1 P1 Clearly identify changes in the
  documents natural language.
• 4.2 P3 Specify the expansion of each
  abbreviation or acronym in a document where it
  first occurs.
• 4.3 P3 Identify the primary natural language of
  a document.

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W3C Guidelines

• Guideline 5 of 14
• Create tables that transform gracefully

• 5.1 P1 Identify row and column headers for data
  tables.
• 5.2 P1 Use mark up to associate data cells and
  header cells.
• 5.3 P2 Do not use table for layout unless they
  make sense when linearized.
• 5.4 P2 If a table is used for layout, do not
  use any structural markup for the purpose of
  visual formatting.
• 5.5 P3 Provide summaries for tables.
• 5.6 P3 Provide abbreviations for header labels.

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W3C Guidelines

• Guideline 6 of 14
• Ensure that pages featuring new technologies
  transform gracefully

• 6.1 P1 Organize documents so that they may be
  read without style sheets.
• 6.2 P1 Equivalents for dynamic content must be
  updated whenever the dynamic content changes.
• 6.3 P1 Ensure that pages are usable when
  scripts, applets, etc are turned off or not
  supported.
• 6.4 P2 Ensure that event handlers are input
  device independent.
• 6.5 P2 Ensure that dynamic content is
  accessible or provide an alternative.

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W3C Guidelines

• Guideline 7 of 14
• Ensure user control of time-sensitive content
  changes

• 7.1 P1 Avoid causing the screen to flicker.
• 7.2 P2 Avoid causing the content to blink.
• 7.3 P2 Avoid movement in pages.
• 7.4 P2 Do not create periodically refreshing
  pages.
• 7.5 P2 Do not use mark up to redirect pages
  automatically.

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W3C Guidelines

• Guideline 8 of 14
• Ensure direct accessibility of embedded user
  interfaces

• 8.1 P1, P2 Make programmatic elements such as
  scripts and applets directly accessible or
  compatible with assistive technologies.

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W3C Guidelines

• Guideline 9 of 14
• Design for device-independence

• 9.1 P1 Provide client-side image maps instead
  of server-side image maps.
• 9.2 P2 Ensure that any element that has its own
  interface can be operated in a device independent
  manner.
• 9.3 P2 Specify logical event handlers (on mouse
  over, on click, etc).
• 9.4 P3 Create a logical tab order through
  links, form controls and objects.
• 9.5 P3 Provide keyboard shortcuts to important
  links.

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W3C Guidelines

• Guideline 10 of 14
• Use interim solutions (so that older browsers and
  assistive technologies will operate correctly)

• 10.1 P2 Do not cause pop-ups, new windows, or
  change in current window to occur without
  informing the user.
• 10.2 P2 Ensure explicit associations between
  labels and form controls.
• 10.3 P3 Provide a linear text alternative for
  tables that layout text in parallel, word-wrapped
  columns.
• 10.4 P3 Place holding characters in edit boxes
  and text areas.
• 10.5 P3 Include non-link printable characters,
  (surrounded by spaces) between adjacent links.

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W3C Guidelines

• Guideline 11 of 14
• Use W3C technologies and guidelines

• 11.1 P2 Use W3C technologies when they are
  available and appropriate for a task (HTML 4.0).
• 11.2 P2 Avoid depreciated features of W3C
  technologies.
• 11.3 P3 Provide information so that users may
  receive documents according to their preference.
• 11.4 P1 If after best efforts, you cannot
  create an accessible page, provide a link to an
  alternative page.

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W3C Guidelines

• Guideline 12 of 14
• Provide context and orientation information (to
  help users understand complex pages or elements)

• 12.1 P1 Title each frame to facilitate frame
  identification and navigation.
• 12.2 P2 Describe the purpose of frames and how
  they relate to each other.
• 12.3 P2 Divide large blocks of information into
  more manageable groups.
• 12.4 P2 Associate labels explicitly with their
  controls in a form.

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W3C Guidelines

• Guideline 13 of 14
• Provide clear navigation mechanisms

• 13.1 P2 Clearly identify the target of each
  link.
• 13.2 P2 Provide metadata to pages and sites.
• 13.3 P2 Provide information about the general
  layout of a site.
• 13.4 P2 Use navigation mechanisms in a
  consistent manner.
• 13.5 P3 Provide navigation bars to provide
  access to the navigation mechanism.
• More!

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W3C Guidelines

• Guideline 13 of 14
• Provide clear navigation mechanisms

• 13.6 P3 Group related links and provide a
  method to bypass the group.
• 13.7 P3 If a search is provided, enable
  different types of searches.
• 13.8 P3 Place distinguishing information at the
  beginning of headings, paragraphs, lists, etc.
• 13.9 P3 Provide information about document
  collections (documents comprising multiple
  pages).
• 13.10 P3 Provide a means to skip over
  multi-line ASCII art.

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W3C Guidelines

• Guideline 14 of 14
• Ensure that documents are clear and simple

• 14.1 P1 Use the clearest and simplest language
  appropriate for the sites content.
• 14.2 P3 Supplement text with graphic or
  auditory presentations where they will facilitate
  the comprehension of the page.
• 14.3 P3 Create a style of presentation that is
  consistent across pages.

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WCAG 2.0 DRAFT
DRAFT

• Applies to a wider range of current, future, and
  non-W3C Web technologies
• Requirements are more testable
• Techniques are more comprehensive
• Based upon Principles vs. Checkpoints
• Although more comprehensive, most Web sites that
  meet current WCAG 1.0 guidelines should be able
  to pass the majority of WCAG 2.0 principle
  requirements

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What is KCTCS doing about web accessibility?

• The Web Services Peer Team was formed last year
  to develop standards regarding web properties.
  Part of that charge includes drafting
  accessibility standards.
• The Peer Team is consulting with KCTCS legal to
  determine the minimum level of compliance
  required by law.
• From there, the Content and Accessibility
  sub-team will make further recommendations
  regarding compliance.
• Your input is welcome!

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Web Accessibility Resources

• http//www.section508.gov/
• http//www.webaim.org/
• http//www.w3.org/TR/WAI-WEBCONTENT/