Markup Tools

Image Guidelines

Computers and the web are primarily a visual medium. In Building Accessible Websites, author Joe Clark asserts that by making all the images on your website accessible, you are over halfway toward your goal of accessibility. Below is a list of guidelines to follow:

• Images should not rely on colors alone to convey important meaning. This also applies to color selections for text, background, etc.
• All images—including and especially imagemaps—must have text equivalents.

XHTML tools for images

There are three key accessibility attributes for images:

• The "alt" attribute
  This provides a string of text briefly describing the contents of an image. It is intended as an alternate text; i.e. a replacement.
• The "title" attribute
  This attribute provides additional information, and is typically displayed as a "tool tip" on graphical browsers.
• The "longdesc" attrubute
  allows you to link to longer descriptions for more complicated graphics such as charts, or more detailed explanations of images. This is not yet widely supported.

When using image maps, you should provide a title for the <map> element, as well as titles and alts for each of the areas that compose the map.

Navigation Guidelines

As previously mentioned, two of the most important things to aim for when coding with accessibility in mind are simplicity and redundancy: Avoid confusing, convoluted tables, forms, and layouts, and providing multiple ways to convey information.

Because of the time-intensive nature of reading Web sites in Braille, Web developers should consider simplifying their pages as much as possible, so that deaf-blind individuals are not required to read extraneous or irrelevant content. These devices emulate the functionality of the standard keyboard, to one degree or another, so keyboard access to Web sites is paramount

Everyone benefits from well-designed Web sites, regardless of cognitive capabilities. In this context, "well-designed" can be defined as having a simple and intuitive interface, clearly worded text, and a consistent navigational scheme between pages.

• provide a way for the end-user to skip over long lists of links
• make sure that your site is accessible via keyboard.

XHTML tools for Navigation

• anchors
  if you have long lists of links on your page, you should provide a link at the beginning to an anchor (#) later in the page to allow users to skip past navigation to the content.
• the "accesskey" attribute
  allows you to specify a character that will activate the associated element (follow a link, submit a form). This attribute is not widely or uniformly supported, and there are guidelines you should follow when using it.
• the "tabindex" attribute
  allows you to specify a positive integer, indicating the order in which page elements will receive focus. Again, there are some guidelines to follow.
• javascript events
  you should avoid using javascript events such as onchange for pull-down menus that automatically perform actions (e.g. form submission). Some users must increment through a list and cannot select the desired option in one step.

Accessibility information available at http://www.webaim.org

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