Web Accessibility refers to the practice of making Web pages accessible to people using a wide range of user agent software and devices, not just standard Web browsers. This is especially important for people with disabilities such as visual impairment.
In order to access the Web, some users require special software or devices in addition to a standard web browser, or specially designed web browsers. Design for accessibility is a sub-category of good design for usability.
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 colour 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;
- 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.;
- Auditory: Deafness or hearing impairments, including individuals who are hard of hearing;
- Seizures: Photoepileptic seizures caused by visual strobe or flashing effects.
Benefits of Web Accessibility
Designing websites with accessibility in mind can often enhance usability for all users. Good design can also deliver easier access for automated software programs that read website content, such as search engines. One important aspect of accessibility is to let people access content in their preferred way. This can also benefit all users not just those with disabilities: for example, some users may wish to adjust text sizes because they are using a very small display on a mobile phone, or may need to use keystrokes to control their computer because they do not have a mouse or prefer not to use one. Search engines generally cannot make much use of graphics.
Different sites will require different degrees of concern for accessibility. For example,
- a site providing information specific to Attention-Deficit/Hyperactivity Disorder (ADHD) needs to be easily accessible by people with ADHD (although you must keep in mind that other users may also wish to access the same information)
- a government site of general interest or a resource directory for people in crisis would need to take into account as many disabilities as possible in order to be available to all citizens.
Users with dyslexia or ADHD will want to stop moving images on the screen because they are easily distracted. People with ADHD may also be confused or distracted by link-rich sites because they can have difficulty when presented with so many options.
Hyperlinks that can only be followed by clicking on them with a mouse are impossible to use for people who can only use a keyboard or screen reader to interact with their computer.
Information provided only in audio format cannot be accessed by people who are deaf. And if provided only in graphic format, information is invisible to people who are blind.
Designing sites in accordance with Web accessibility principles is necessary to enable access for all users.
References:
- The Web Accessibility Initiative (WAI)
- The World Wide Web Consortium (W3C) Web accessibility guidelines and resources.
- Article Source: http://en.wikipedia.org/wiki/Web_accessibility
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