Designing Accessible Websites

Accessibility concerns a large number of people. Some users have learning disabilities, speak English as a second language, or are younger than the average user. These people may have difficulty navigating sites that are poorly designed with unclear directions. Even the "average" user may have encountered problems in accessing Web content. For example, some users use slow connections and modems or older equipment that cannot download large files.

For users with various disabilities, accessibility is even more of an important issue. According to various national and government surveys, nearly 50 million people (nearly 20 percent of the population) in the United States have either a severe or functional disability, as many as 500 million people have disabilities worldwide, and about 8 percent of Americans who use the Web have a disability. It is important to note that while many people are born with a disability, others may become part of the disabled population because of aging, accidents, or diseases. These changes may be temporary or permanent.

Generally, Web access is limited by five types of disabilities. Note that each impairment requires unique design considerations, which will not be detailed here but for which resources will be given later.

Visual Impairments

Visual impairments include dimness, haziness, extreme far-sightedness or near-sightedness, color blindness, tunnel vision, and blindness. Instead of using a monitor or mouse, blind users employ a screen reader, which translates text into speech. Because a screen reader cannot interpret the graphical content of images, alternative tags, or "ALT" tags, are used to allow users to hear the alternative text about the images. For people who have low vision, text size and color can make a big difference.

Hearing Impairments

Like visual impairments, hearing impairments also cover a wide range, from being able to hear some sound, but not being able to distinguish words, to not being able to hear at all. The most obvious solution is synchronized captioning and/or transcripts for all aurally imparted information.

Mobility impairments

A variety of diseases can cause mobility impairments: arthritis, stroke, cerebral palsy, Parkinson’s disease, multiple sclerosis, and loss of limbs or digits. These conditions make using standard keyboards and mouse devices difficult.

Cognitive and language impairments

This category consists of dyslexia, difficulties remembering, solving problems, or perceiving sensory information, problems comprehending and using language. For people with these impairments, complex or inconsistent displays or word choice can add to the difficulty of accessing and comprehending Web content.

Seizure disorders

Some susceptible individuals can be induced into seizures with elements that flicker between 2 Hz and 55 Hz.

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