Making applets and plug-ins accessible

Requirement: If a page requires the use of a plug-in or applet, the plug-in or applet and its means of downloading and installation must be accessible. Otherwise, the content accessed via the plug-in or applet must be presented in an alternative accessible form.

Plug-ins are small applications you typically download and install on your computer that interact with a Web browser. These plug-ins can function like a helper application -- the Web browser itself might not be able to act on a particular element, but this application can.

However, there are several usability and accessibility issues related to plug-ins.

First, you should provide links to where users can download the plug-in. The downloading and installation should be accessible.

Second, the plug-in and the content it accesses must be accessible. For example, many people use a tool called Flash to make and display presentations on the Web. Currently, Flash is not very accessible to users on text-only systems or those with visual impairments. Therefore, developers can't rely Flash alone for conveying content.

In this case, developers should provide accessible alternative content for the Flash presentation. If the presentation is used only for effect, developers must still provide a link to some descriptive text about the presentation.

Java applets and other embedded programs can also suffer these problems. Developers might assume a user can see the content and is able to use a mouse to interact with the applet controls. However, the user might have no mouse and instead uses just keyboard shortcuts. In those cases, the applet's controls must have have keyboard equivalents. Likely, there should be other text-based cues to help the user understand how to use the applet.

Adobe Acrobat (PDF) files are not very accessible. While Acrobat 5.o includes some accessibility features, often the documents are not as accessible as they should be. If a PDF version is provided an HTML or text-based version should also be offered.

PowerPoint presentations for the most part are not accessible using the free PowerPoint viewer plug-in. If users have a full version of PowerPoint on their computers, the presentations will be more accessible. The PowerPoint presentation should be converted to HTML, complete with alt attributes for an images.

The bottom line about plug-ins and accessibility is that most are not fully accessible. Developers should provide links to a place where users can download the plug-ins. They should provide the content in accessible alternative form (such as HTML or text) and where practical, give users the option of choosing the form they would like file in.