(h) Markup shall be used to associate data cells and header cells for data tables that have two or more logical levels of row or column headers.
Don't use nested tables (tables within tables) in template design.
(i) Frames shall be titled with text that facilitates frame identification and navigation.
No design need justifies the use of frames. Frames are the most confusing element for assistive technology and should be avoided at all costs.
(j) Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.
Don't use "blink" tag or any kind of dynamic elements on the page to prevent the possibility of flickering.
(k) A text-only page, with equivalent information or functionality, shall be provided to make a web site comply with the provisions of this part, when compliance cannot be accomplished in any other way. The content of the text-only page shall be updated whenever the primary page changes.
When 508-compliant template design is not possible through any other means, create a separate 508-compliant template, with simplified text-only navigation.
(l) When pages utilize scripting languages to display content, or to create interface elements, the information provided by the script shall be identified with functional text that can be read by assistive technology.
Don't use client-side scripting for template design. If the use of scripting is unavoidable, make sure to test the template to ensure that the template functions with the scripting turned off.
(m) 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).
Avoid using applets or plug-ins on the template or page. If the use is unavoidable, make sure that client-side application being used complies with §1194.21(a) through (l).