Constructing a POUR Website
All forms of communication require input into the brain via at least one of the senses of the body. The Internet is a medium of communication providing access to knowledge and processes through electronic means. The most relevant senses in this context are sight, hearing, and touch. (Other animals have learned elaborate communication systems through taste and smell, but we humans are comparatively deficient in that department. Besides, tastes and smells are harder to transmit electronically.)
Any discussion of web accessibility is based upon the assumption that people need to be able to perceive web content. They need to be able to input the information into their brain so that they can process it. If the information cannot get into the brain, it is inaccessible. As obvious as that statement may sound, it is a principle which is frequently ignored by developers. Too many sites contain web content that cannot even be perceived by some of the people who would like to access it.
People with full use of their vision are able to read text, view images, understand the visual cues afforded by web page layouts, understand the symbolic meaning of colors in certain cultural contexts (as with red and green street lights, or blue and pink baby clothing), and in general can use their eyes to make sense of information that is presented to them. This mode of perception—from the eye to the brain—is powerful, and Web developers should take full advantage of its communicative strengths. Visual perception is especially important to individuals who lack one of the other main communicative senses, such as people who are deaf. For such individuals, their remaining senses take on heightened importance.
However, there are people who cannot take full advantage of this mode of communication. Some people have no vision at all. Others have a limited amount of vision. For these individuals, other modes of communication are necessary. In some cases this means that information must be converted into a format which they can more easily perceive, such as an audio format. Assistive technologies can perform this conversion, but only if the content is designed with accessibility in mind.
See also Visual Disabilities.
Oral conversations between people are a daily occurrence. People talk at home, in the office, on the phone, and, increasingly, on the Internet. The Internet enables people to engage in voice chats, to leave voice messages, to watch videos, to hear music, to listen to web radio broadcasts, and to participate in numerous other kinds of audio interactions with other people or with electronic content prepared by other people. The number and kinds of audio interactions will only increase as Web technologies mature and proliferate.
Technologies and methods exist for making audio information available to people who cannot hear it. These technologies and methods cannot help anybody though unless someone actually uses them to make the information accessible to people who cannot hear it.
See also Auditory Disabilities.
For most people, touch is not their main form of communication. For them, touch may have relevance for indirect expressions of solidarity, as in romantic relationships (physical intimacy), among friends (hugs, high-fives, handshakes), with children (rocking babies to sleep, holding children when they're scared), and other situations that communicate emotions but which do not directly communicate information per se.
For individuals who have neither sight nor hearing, touch is the most important form of communication of all. Interpersonal communication is possible through sign language, in which two people use their hands to feel each other's gestures, signed language, and body movements. The fingers can be used to perceive textual information printed in Braille formats. In fact, refreshable Braille devices can convert text into Braille output for use on the web.
For more information, read the Screen Readers section of the Blindness article.
Since not everyone has the same abilities or equal use of the same senses, one of the main keys to accessibility is ensuring that information is transformable from one form into another, so that it can be perceived in multiple ways. Text can be transformed into audio and into Braille by the assistive technologies used by people with disabilities. Audio can be transformed into text, but this must be done before it reaches the user, because technologies to automatically convert audio to text are usually unreliable and not commonly available to users who might need them. Graphics, animations, and videos are similar to audio in the sense that developers must provide the text alternative to users.
Overall, text is the most easily and most universally transformable format. However, this does not mean that web accessibility means an end to all non-text elements. On the contrary, the non-text elements in many cases are crucial to accessibility, as explained in Text-only Versions.
The take-home message is that the information must be perceivable somehow. That is the first step to accessibility upon which all others are based, and without which accessibility cannot happen.
Content vs. Style and Presentation
The main content should be separable from the way it is styled or presented. Even though styling can enhance the user experience, and in some cases even improve comprehension, the main message should not depend on the mode of presentation. Semantic structure and meaning should be independent of the "look and feel." This is important because not all users will be able to perceive the presentational look and feel aspects of web content. When the presentation is disabled, the web content should still be able to communicate its message effectively.
See Creating Semantic Structure for more information.
In addition, background colors, graphics, and sounds should not interfere with the content. If the main content is presented in an audio format, background sounds should not obscure the message. Content presented in a visual format should likewise be distinguishable from extraneous stylistic visual elements. Text should be distinguishable from its background.