M. Plugins

Checkpoint (M) focuses on a web page requires that an applet, plugin or other application be present on the client system to interpret page content. The page must provide a link to a plugin or applet that complies with Checkpoint (A) through (L).


While most web browsers can easily read HTML and display it to the user, several private companies have developed proprietary file formats for transmitting and displaying special content, such as multimedia or very precisely defined documents. Because these file formats are proprietary, web browsers cannot ordinarily display them. For these files to be viewed by web browsers, add-on programs or "plugins" must be downloaded and installed on the user's computer These programs must meet the software accessibility guidelines. This provision requires that web pages that provide content such as Real Audio or PDF (Adobe's Portable Document Format) files also provide a link to a plugin that will meet the software accessibility provisions.


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Departmental Web Developer Form

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This provision places a responsibility on the web page author to know that a compliant application exists, before requiring a plugin.

Developer requirements

To ensure that a web site that uses a plugin is accessible, the developer must ensure three things.

  1. The plugin software meets accessibility standards. This will either be listed on the company's web site, or you may contact them and ask if they meet the Section 508 software accessibility guidelines.
  2. The content for the plugin is accessible. This requires that the developer make all content used for that plugin in an accessible manner.
  3. That they have included a link to the necessary plugin and any required accessibility plugins on all pages that include the plugin content. When possible use the links provided on the Missouri State web plugins page as links for your plugins.

Free accessible plugins

Following is a link to some of the more common free and accessible plugins that may be required on the Missouri State web site.

See the Missouri State Web Browser Plugins page.

Additional resources for vendors' accessible products

Adobe Accessibility Resource Center topics include:

Making multimedia accessible

For more information about how to make multimedia accessible using QuickTime, RealAudio, and Media Player, see Checkpoint (B).

This page adopted from the Access Board 508.