Alternative text is a textual description of an image. It is used in web browsers in place of displaying an image. People with visual disabilities need assistance in understanding what message an image is trying to convey because they cannot see, or have difficulty seeing the image. In addition, some web browsers do not support images (i.e.: handheld devices).
For people with visual disabilities the Alternative Text is read by screen readers to describe an image. The purpose of Alternative Text is to provide an experience as close as possible to that of being able to actually see the image, even when the image is never actually "seen".
Types of Alternative Text
There are three basic types of Alternative Text:
1. Alt tag - an "Alt Tag" is a short description, usually 8-10 words, or less. The "Alt Tag" is embedded directly in the web page.
2. Long Description - a description that is usually longer than 8-10 words. It is accessed through a "d" link. A "d" link allows people to click on the small letter "d" next to the image to open up a new page containing the entire presentation.
3. Decorative Image - an image that is used purely for decoration and does not add or take away anything significant from the message of the page. An example would be a line which is used to visually separate two items on a screen , like a line separating the Title of a page from the content of a page. When an image is encoded as a a "Decorative Image" it is assigned a null tag which tells a screen reader to ignore it.
Much of the timeline requirements for Section 508 accessibility standards compliance are already in place, with the exception of those websites for which remediation or replacement of the website is not possible or would constitute an undue burden, then a plan to provide an equally effective alternate form of access must be developed, documented, and communicated.
By May 15, 2012, all websites in the California State University system should fully conform to Section 508; the undue burden exception and requirements as described above continue to apply.
The full timeline published by the Chancellor's Office as part of the Accessible Technology Initiative is available on the HSU Accessible Technology Initiative website.
An electronically-provided ATI class is mandatory for faculty and staff publishing official web pages. Part of those training materials includes training on a product called AccVerify. This is an automatic web accessibility checker program that can check the accessibility of web pages. Keep in mind though, that not everything on a web page can be checked automatically. There are some manual checks that the developer/user has to perform. The training will cover the use of the AccVerify software in addition to how to perform the manual checks to do a complete check of a website.