Unless carefully designed, the use of FRAMES can create a page which is very inaccessible to persons with visual impairments who use screen-reading technology, and to persons with browsers that do not support FRAMES.
"Frames" are the latest method of formatting a screen, but frames are not widely supported (yet). For the purposes of universal accessibility, use of FRAMES on a web-site falls under the injunction against using browser-specific constructs, and should be avoided.
However, if you do use FRAMES, here are some tips on how to make your site as accessible as possible.
HTML allows a FRAME developer to include an alternative set of HTML instructions to be executed or displayed if the end-user's browser does not support FRAMES. Including an effective alternative to the FRAME page is equivalent to including ALT=TEXT with a graphic image: it gets your critical information across to everyone. Keep in mind though, your alternative HTML should be accessible -- using TABLES as an alternative to FRAMES is not a good idea, since TABLES are inaccessible to many users too.
This link takes you to a page that incorporates frame technology. If you are using a FRAME-aware browser, you will have to view the source file to see the accessible HTML alternatives. If you are using a browser that cannot view frames, you will see the accessible alternative I have programmed to convey the page's critical information. If you are using a FRAME-aware browser and cannot access either the FRAME display or the accessible alternative, then you have hit upon the essential reason for not using frames on a site: some users will not be able to benefit from your site.
Avoid using FRAMES, but if you must, please include an accessible alternative, either as a separate page, or by including the accessible HTML for FRAME-unaware browsers.

Making Links Accessible.
Are Adobe PDF documents accessible?



