Alternative text, sometimes called alt text, is a method of providing equivalent text for non-text elements, such as images, objects, and applets. W3C® has recommended that alt text be no longer than 150 characters.
An applet is a little application. An applet can accompany a Web page, so that tasks can be performed without having to send a request back to the server.
ASCII art is an image created using text characters and symbols. An example of this is a smiley face, :-).
Assistive technologies describe methods that enhance the way users access Web content. These methods can include:
A client-side image map displays the active regions of an image map without a script, or set of instructions, from the server. The client-side image map is preferable to the server-side image map for accessibility.
A crawler visits documents and their contents to gather information.
The dynamic content of a Web page is the information that allows a page to be responsive to user actions. For example, when the user points to text, it changes color.
The element content is the information that is available to the Web user when the Web element is not supported by the user agent or browser.
Something is equivalent when it conveys the same information as the original item. Accessibility standards have equivalent text, and sometimes, equivalent pages.
A frame is part of a Web page that can be controlled independently. For example, a Web page might include frames, one containing links and another containing the unique text that appears on the page.
An image map is a graphic that contains links.
A long description, created by using the longdesc attribute in HTML, is a method of providing equivalent text for non-text elements, such as images, objects, and applets. The text value for a long description is the URL where the long description is available. Because some browsers do not support the longdesc attribute, you should use both alternative text and long descriptions for Web elements that require a long description.
A script is a set of directions written in one program to be interpreted by another program. For example, a script can provide your browser with a sequence of instructions on how to display a Web page with animations and sounds.
A server-side image map requires a script, or set of instructions, from the server to display the active regions of the image map. The client-side image map is preferred for accessibility.
A style sheet is the default template for one or more pages. The style sheet includes information about the appearance and layout of a page, and is often applied to a group of pages to attain consistency.