508
Section 508 of the Rehabilitation Act was enacted to eliminate barriers in information technology, to make available new opportunities for people with disabilities, and to encourage development of technologies that will help achieve these goals. Under Section 508 (29 U.S.C. § 794d), Federal Agencies must give disabled employees and members of the public access to information that is comparable to the access available to others.
Resource: http://www.section508.gov/
Accelerator keys
Combinations of characters that allow users to make software commands instead of interacting with menu options or different levels of a user interface, also known as keyboard shortcuts.
Accessibility
The measure of a web page’s usability by persons with one or more disabilities.
Within these guidelines, “accessible Web content” and “accessible authoring tool” mean that the content and tool can be used by people regardless of disability. To understand the accessibility issues relevant to authoring tool design, consider that many authors may be creating content in contexts very different from your own:
- They may not be able to see, hear, move, or may not be able to process some types of information easily or at all;
- They may have difficulty reading or comprehending text;
- They may not have or be able to use a keyboard or mouse;
- They may have a text-only display, or a small screen.
Accessible design will benefit people in these different authoring scenarios and also many people who do not have a physical disability but who have similar needs.
Alternative Text
Short text used to describe non-text content—usually 125 characters or less. Content is “equivalent” to other content when both fulfill essentially the same function or purpose upon presentation to the user.
Assistive technologies
Technologies (software or hardware) that increase, maintain, or improve the functional capabilities of individuals with disabilities when interacting with computers or computer-based systems.
Audio browsers
Web browsers that provides a text-to-speech capability for the blind and visually impaired.
Audio description
An audio description is either a prerecorded human voice or a synthesized voice (recorded or generated dynamically) describing the key visual elements of a movie or other animation. The audio description is synchronized with (and possibly included as part of) the audio track of the presentation, usually during natural pauses in the audio track. Audio descriptions include information about actions, body language, graphics, and scene changes.
Captions
“Captions” are essential text equivalents for movie audio. Captions consist of a text transcript of the auditory track of the movie (or other video presentation) that is synchronized with the video and auditory tracks. Captions are generally rendered graphically and benefit people who can see but are deaf, hard-of-hearing, or cannot hear the audio.
Clickability cues
A visual indication that a given word or item on a Web page is clickable. Cues that can be used to indicate the clickability of an item include color, underlining, bullets, and arrows.
Cognitive and Neurological Disabilities
- Dyslexia, Dyscalculia
- Attention Deficit Disorder, or ADD
- Attention Deficit Hyperactive Disorder, or ADHD
- Impairments of Intelligence, or Learning Disabilities
- Memory Impairments
- Mental Health Disabilities
- Seizure Disorders
Color Blindness
Color blindness is a lack of sensitivity to certain colors. Common forms of color blindness include difficulty distinguishing between red and green, or between yellow and blue. Sometimes color blindness results in the inability to perceive any color.
Contrast
A difference in visual attributes (e.g., hue, lightness, saturation) of an object’s foreground and background.
Device-dependent
Used to describe event handlers that require a specific kind of input device. For example, onDblClick requires a mouse; there is no keyboard equivalent for double clicking. Input devices may include pointing devices (such as the mouse), keyboards, braille devices, head wands, microphones, and others. Output devices may include monitors, speech synthesizers, and braille devices. Scripting should be device-independent or provide multiple input and output options for different devices.
Device-Independent
Users must be able to interact with a word processor (and the document it renders) using the supported input and output devices of their choice and according to their needs. Input devices may include pointing devices, keyboards, braille devices, head wands, microphones, and others. Output devices may include monitors, speech synthesizers, and braille devices.
Note: That “device-independent support” does not mean that devices must support every input or output device. User agents should offer redundant input and output mechanisms for those devices that are supported.
Example: If a supports keyboard and mouse input, users should be able to interact with all features using either the keyboard or the mouse.
Device-independence refers to the desirable property that operation of a user agent feature is not bound to only one input or output device.
Disability
A physical or mental condition that limits a person’s movements, senses, or activities.
Graceful Degradation
When a site utilizes new technology, if disabled, the content maintains effectiveness for the users.
Since HTML is continually changing and different browsers support different elements, graceful degradation is the key to making sure that pages are readable and accessible in all browsers. When a browser encounters tags it doesn’t understand or can’t display, degradation takes place. Whether this degradation will cause some of your page content to be lost to the browser, or whether the content of your page can still be accessed fully is dependent on whether the degradation is graceful.
The HTML standards were written with graceful degradation in mind – new attributes to older tags are safely ignored so that the rest of the tag can still function normally, and new tags are written with alternative display for browsers that don’t support them in mind. There are many elements of HTML that can’t be displayed or can be turned off in browsers that were written with the knowledge of these elements- such as images, java, and frames. Using the appropriate methods to provide an alternative message to those who can’t see those elements or have turned them off is one way to design for graceful degradation.
If you design pages with graceful degradation in mind, by utilizing the built in elements of the HTML standards, and the advice provided here, you can design pages that should degrade gracefully in all browsers and are accessible.
Hearing Disabilities
- Deafness
- Hard of Hearing
Keyboard Equivalents
Keys or key combinations that provide access to keyboard functions that are usually activated by a pointing device, voice input, or other input or control mechanisms/devices.
Long Descriptions
Descriptions that are written for complex figures and tagged via the long desc attribute; though not currently supported by most Web browsers, the long desc attribute is a planned feature in the next iteration of Firefox.
Luminance Contrast Ratio
A measure of the difference in contrast between foreground and background; specific minimal values are recommended via WCAG 2.0.
Photosensitive Epilepsy/ Photoepilepsy
Some people with epilepsy can be triggered into seizures by flashing or flickering lights and rapidly changing images or visual patterns. This is called photosensitive epilepsy.
Programmatic Focus
Programmatic focus refers to the programming language that is exposed to assistive technology to indicate where user interaction will take place.
Resource: http://www.section508.gov/
Screen Magnifier
A software program that magnifies a portion of the screen, so that it can be more easily viewed. Screen magnifiers are used primarily by individuals with low vision.
Screen reader
A software program used to allow reading of content and navigation of the screen using speech or Braille output. Used primarily by people who have difficulty seeing. JAWS and NVDA are examples. Screen readers can usually only read text that is printed, not painted, to the screen.
Tab Order
An assistive technology strategy. For people who cannot use a mouse, one strategy for rapidly scanning through links, headers, list items, or other structural items on a Web page is to use the tab key to go through the items in sequence. People who are using screen readers — whether because they are blind or dyslexic — may tab through items on a page, as well as people using voice recognition.
Transcript
A text only version of what’s said in a movie or television program; they are not real time and they generally are limited to speech only; they are not a recommended substitute for captions.
Visual Focus
Where the user’s focus is on a Web page; generally represented by a dashed box that appears around items on the page and associated with tabbing.
WAI-ARIA (Accessible Rich Internet Applications)
WAI-ARIA is a specification published by the World Wide Web Consortium that specifies how to increase the accessibility of dynamic content and user interface components developed with Ajax, HTML, JavaScript and related technologies.
WCAG 2.0
The Web Content Accessibility Guidelines (WCAG) 2.0 is focused on providing an international technical standard for web content. It has 12 guidelines that are organized under four principles: perceivable, operable, understandable, and robust. The guidelines each have a testable success criteria, which are at three levels: A, AA, and AAA.