When a web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21 (a) through (l).

Why this is important: This checkpoint has become substantially more complicated to evaluate since it was written. There are two problems here. The first, "applets," can be thought of as true computer applications running within a browser; for example, Java or ActiveX controls—these will have to meet the separate Section 508 standards for all computer software. The second, "plug-ins," could mean anything from Flash to Quick-time to PDF or even Word. Most browsers now provide built-in rendering for many of these formats, but many assistive technologies probably won't. Equivalent content will have to be provided for a large range of disabilities; for example, closed captioning of video and transcripts of audio—and formats such as PDF will have to be coded with current accessibility techniques.