What are some of the considerations you should keep in mind for persons with disabilities using these different technologies for delivering content?
Blindness: Examples of barriers that people with blindness may encounter on the Web can include:
- images that do not have alternative text
- complex images (e.g., graphs or charts) that are not adequately described
- video that is not described in text or audio
- tables that do not make sense when read serially (in a cell-by-cell or "linearized" mode)
- frames that do not have "NOFRAME" alternatives, or that do not have meaningful names
- forms that cannot be tabbed through in a logical sequence or that are poorly labelled
- browsers and authoring tools that lack keyboard support for all commands
- browsers and authoring tools that do not use standard applications programmer interfaces for the operating system they are based in
- non-standard document formats that may be difficult for their screen reader to interpret
Low vision: Barriers that people with low vision may encounter on the Web can include:
- Web pages with absolute font sizes that do not change (enlarge or reduce) easily
- Web pages that, because of inconsistent layout, are difficult to navigate when enlarged, due to loss of surrounding context
- Web pages, or images on Web pages, that have poor contrast, and whose contrast cannot be easily changed through user override of author style sheets
- text presented as images, which prevents wrapping to the next line when enlarged
- also many of the barriers listed for blindness, above, depending on the type and extent of visual limitation
Color blindness: Barriers that people with color blindness may encounter on the Web can include:
- color that is used as a unique marker to emphasize text on a Web site
- text that inadequately contrasts with background color or patterns
- browsers that do not support user override of authors' style sheets
Deafness: Barriers that people who are deaf may encounter on the Web can include:
- lack of captions or transcripts of audio on the Web, including webcasts
- lack of content-related images in pages full of text, which can slow comprehension for people whose first language may be a sign language instead of a written/spoken language
- lack of clear and simple language
- requirements for voice input on Web sites
Hard of hearing: Barriers encountered on the Web can include:
- lack of captions or transcripts for audio on the Web, including webcasts
Motor disabilities: Barriers that people with motor disabilities affecting the hands or arms may encounter include:
- time-limited response options on Web pages
- browsers and authoring tools that do not support keyboard alternatives for mouse commands
- forms that cannot be tabbed through in a logical order
Visual and Auditory Perception: Barriers that people with visual and auditory perceptual disabilities may encounter on the Web can include:
- lack of alternative modalities for information on Web sites, for instance lack of alternative text that can be converted to audio to supplement visuals, or the lack of captions for audio
Attention deficit disorder: Barriers that people with attention deficit disorder may encounter on the Web can include:
- distracting visual or audio elements that cannot easily be turned off
- lack of clear and consistent organization of Web sites
Intellectual disabilities: Barriers can include:
- use of unnecessarily complex language on Web sites
- lack of graphics on Web sites
- lack of clear or consistent organization of Web sites
Memory impairments: Barriers can include:
- lack of clear or consistent organization of Web sites
Mental health disabilities: To Barriers can include:
- distracting visual or audio elements that cannot easily be turned off
- Web pages with absolute font sizes that do not enlarge easily
How People with Disabilities Use the Web. http://www.w3.org/WAI/EO/Drafts/PWD-Use-Web/#onlinestudent. W3C, 5 May 2005.
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