The World Wide Web
Consortium (W3C) has created a set of guidelines to help web authors
create web pages that make the Internet accessible to all. ITS encourages
web authors to design pages that meet the minimum standards set forth in
the W3C Web Accessibility Initiatives. For more details on HTML tagging
and design, please refer to the list of URL's at the bottom of this
document. The most critical design considerations can be summarized as
text for all images and image maps in your document. The syntax for
including alternate text is shown in this example:
alt="This is an image with alternate text.">
The alternate text is displayed when the mouse pointer moves over
the image. Try it!
The same alt
syntax can be used in client-side image maps to provide alternate text
for each link area in the image. Be sure that the text provides an
adequate description of the link's target for a user who may be
relying on a screen reader or other assistive technology to read the
Identify row and
column headers in tables. This can be accomplished by use of the <thead>,
<tbody> and <th> tags, which separate table headers from
table data. For example:
The HTML 4.0
table tags allow data to be associated with a specific header and
for multiple columns to be grouped together. If you are creating
complex tables in HTML, it is advisable to consult an HTML 4.0
reference book and the W3C guidelines for advice on how to create
accessible data tables. Note that the W3C recommends that the use of
tables purely for screen formatting be kept to a minimum.
If you use
Cascading Style Sheets in your page, be sure that the page
organization will still be coherent when it is viewed by a browser or
screen reader that does not support CSS.
Be sure that the
text and background colors provide sufficient contrast. Consider that
color-blind readers may have difficulty distinguishing text and
Provide titles for
each document frame in a frame set.
descriptions for all multimedia content, scripts, ascii art, images
used as list bullets, spacers, graphical buttons, sounds (played with
or without user interaction), stand-alone audio files, audio tracks of
video, and video.
Do not cause the
screen to flicker.
If all else fails,
present the user with the option to view a text-only page.
Yale Web Team, January