What is Accessibility?
Accessibility refers to the design of products, devices, services, or environments for people who experience disabilities. The concept of accessible design and practice of accessible development ensures both "direct access" (i.e. unassisted) and "indirect access" meaning compatibility with a person's assistive technology (for example, computer screen readers).
Accessibility can be viewed as the "ability to access" and benefit from some system or entity. The concept focuses on enabling access for people with disabilities, or special needs, or enabling access through the use of assistive technology; however, research and development in accessibility brings benefits to everyone.
What is Web Accessibility?
Web accessibility refers to the inclusive practice of removing barriers that prevent interaction with, or access to websites, by people with disabilities. When sites are correctly designed, developed and edited, all users have equal access to information and functionality.
The needs that Web accessibility aims to address include:
- Visual: Visual impairments including blindness, various common types of low vision and poor eyesight, various types of color blindness;
- Motor/mobility: e.g. difficulty or inability to use the hands, including tremors, muscle slowness, loss of fine muscle control, etc., due to conditions such as Parkinson's Disease, muscular dystrophy, cerebral palsy, stroke;
- Auditory: Deafness or hearing impairments, including individuals who are hard of hearing;
- Seizures: Photo epileptic seizures caused by visual strobe or flashing effects.
- Cognitive/Intellectual: Developmental disabilities, learning disabilities (dyslexia, dyscalculia, etc.), and cognitive disabilities of various origins, affecting memory, attention, developmental "maturity," problem-solving and logic skills, etc.
Web Accessbility Guidelines
The Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C), the main international standards organization for the Internet. They are a set of guidelines that specify how to make content accessible, primarily for people with disabilities—but also for all user agents, including highly limited devices, such as mobile phones. The current version, WCAG 2.0, was published in December 2008 and became an ISO standard, ISO/IEC 40500:2012 in October 2012.
The WCAG 1.0 was published and became a W3C recommendation on 5 May 1999. They have since been superseded by WCAG 2.0.
WCAG 1.0 consist of 14 guidelines—each of which describes a general principle of accessible design. Each guideline covers a basic theme of web accessibility and is associated with one or more checkpoints that describes how to apply that guideline to particular webpage features.
Guideline 1: Provide equivalent alternatives to auditory and visual content
Guideline 2: Don’t rely on colour alone
Guideline 3: Use markup and style sheets, and do so properly
Guideline 4: Clarify natural language usage
Guideline 5: Create tables that transform gracefully
Guideline 6: Ensure that pages featuring new technologies transform gracefully
Guideline 7: Ensure user control of time sensitive content changes
Guideline 8: Ensure direct accessibility of embedded user interfaces
Guideline 9: Design for device independence
Guideline 10: User interim solutions
Guideline 11: Use W3C technologies and guidelines
Guideline 12: Provide context and orientation information
Guideline 13: Provide clear navigation mechanisms
Guideline 14: Ensure that documents are clear and simple
WCAG 2.0 was published as a W3C Recommendation on 11 December 2008.It consists of twelve guidelines (untestable) organized under four principles (websites must be perceivable, operable, understandable, and robust). Each guideline has testable success criteria (61 in all).
Information and user interface components must be presentable to users in ways they can perceive.
- Guideline 1.1: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
- Guideline 1.2: Time-based media: Provide alternatives for time-based media.
- Guideline 1.3: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
- Guideline 1.4: Make it easier for users to see and hear content including separating foreground from background.
User interface components and navigation must be operable.
- Guideline 2.1: Make all functionality available from a keyboard.
- Guideline 2.2: Provide users enough time to read and use content.
- Guideline 2.3: Do not design content in a way that is known to cause seizures.
- Guideline 2.4: Provide ways to help users navigate, find content, and determine where they are.
Information and the operation of user interface must be understandable.
- Guideline 3.1: Make text content readable and understandable.
- Guideline 3.2: Make web pages appear and operate in predictable ways.
- Guideline 3.3: Help users avoid and correct mistakes.