Understanding accessibility requires an understanding of the importance of structured documents, and the distinction between a typewritten page and a web page.
Some of us grew up using the typewriter to create documents. A typewritten document had little meaningful structure - what was possible was basically visual tricks - the use of indentation, boldface type (if available), italics (perhaps) and "carriage returns" to separate sections of content or make a nicely formatted title page. The structure in a typewritten document is only skin deep, and depends upon the recognition of visual cues.
HyperText Markup Language
The language of the web, hypertext markup language (HTML), provides a rich set of tools to meaningfully structure information. Sections of a page are wrapped in tags, such as:
- < p > ... < /p > to signify a paragraph
- < li > ... < /li > for a list item
- < h1 > ... < /h1 > for a level one header
Extra information can be added as attributes to various HTML elements. This extra information may not be visible to the user. The alt attribute, for example, can be used to provide a short text description of an image. In some browsers, this description will appear when the user hovers the mouse over an image.
The Power of Semantic HTML
When HTML is constructed using semantic tags, it becomes much more than a typewritten page. A web browser or other device can use the semantic information in powerful ways. A few examples:
- To conserve screen space, a mobile device might display a header in boldface, rather than increase the text size.
- Users with low-bandwidth connections may disable images, and will see an image description instead of an image.
- Individuals who are blind or do not use a mouse can use the keyboard to move between headers and other elements.
- Screen reading software can announce the number of items in a list, read only the headings on a page, and provide a list of only the links.
Clearly presented, semantic, and simple HTML generally provides the most accessible content. To learn more about web accessibility, please explore the resources on this section of the website. If you need help with a particular accessibility concern, or want to learn more, contact the Web Services Group.