Please also see my current work at
The Enabled Web.
Section 508 quick reference
Section 508 guidelines are from public law, Rehabilitation Act of 1973,
as amended (29 U.S.C. 794d). WCAG guidelines Copyright © 1994-2006 W3C® (MIT, ERCIM, Keio),
used in accordance with the W3C Document License.
Original portions of this page are Copyright © 2006, Tom Jewett. May be re-posted, printed,
and distributed for non-commercial use with this notice intact.
This page is designed to assist organizations or web developers who, by law or
policy, must comply with Section 508 accessibility standards. It lists in one
place both the Section 508 guidelines and the corresponding WCAG 1.0 checkpoints,
where applicable. For the most recent information, specific techniques, and questions,
please refer to the authoritative sources:
Beyond the checkpoints
Section 508 is designed to "establish a minimum level of accessibility"
Although web developers may concentrate on the technical standards of Subpart B, 1194.22,
they should realize that there is a Subpart C, Functional Performance Criteria (1194.31).
This is the "bottom line": does your site give disabled readers the same
access to information as non-disabled readers have?
From a technical point of view, developers can make their job much easier
by following the most current standards, including XHTML 1.0 Strict and CSS2. In some
cases, XHTML 1.0 Transitional may be necessary to accommodate older browsers and the
limitations of some programming tools. For accessibility standards, W3C WCAG 1.0 goes
beyond Section 508 in several ways, and the soon-to-be-released WCAG 2.0 should be
followed as soon as possible.
Simply passing validity checks for XHTML and CSS is not enough.
Conceptually, there should be complete separation of presentation (CSS) from
document content and structure (XHTML). At a deeper level, there might even be
separation of document structure or syntax (XHTML) from content meaning or semantics
(XML, transformed with XSL).
Each "beyond the checkpoint" bullet below suggests ways
that developers can make their life easier while meeting both the letter and the
intent of the law. These may be most useful in new development, but still might
assist in retrofit of older sites.
New development or retrofit work to 508 standards will require
checking with both automated tools and manual techniques including code inspection.
There are many tools and lists of techniques that can assist in the process. Unfortunately,
none of these are perfect; some are not even complete or correct. Two examples should
- For the "skip links" checkpoint, the Lift® tester fails pages that do not contain
a hidden link, specifically coded using an out-of-date "invisible gif"
method. In fact, low-vision readers need a visible link to
accomplish this task.
- For the same checkpoint, even the WCAG techniques (link above) suggest
using the old HTML 4.1 <MAP> tag that is actually intended to group links
in image maps, not in lists.
Lessons: first, meet the checkpoint as written, not necessarily as interpreted
somewhere else (including here). Second, test to be sure that the site is actually
usable with real assistive technology and by users with a variety of real disabilities.
Finally, don't forget that the site will be read by non-disabled users—it
has to be attractive and useful for them, too!
Guidelines and checkpoints
- Sect 508, 1194.22(a) A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content).
- WCAG 1.1 Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes:
images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and
programmatic objects, ascii art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user
interaction), stand-alone audio files, audio tracks of video, and video.
- Beyond the checkpoint: The "equivalent" text really has to convey the same
information as the non-text element. It may have to be reviewed by someone with domain
expertise to make sure that this is the case. It might even take the form of an
explanatory paragraph that would also be useful to non-disabled readers. The "alt"
tag should be empty (alt="") for any non-text element that does not
convey information (for example, a purely decorative element).
- Sect 508, 1194.22(b) Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.
- WCAG 1.4 For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation.
- Beyond the checkpoint: Doing this well requires specialized professional-level tools and skills. For most
sites, make sure that the multimedia component is really important to the message; if
it's only decoration, it may not be cost-effective.
- Sect 508, 1194.22(c) Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup.
- WCAG 2.1 Ensure that all information conveyed with color is also available without color, for example from context or markup.
- Beyond the checkpoint: The color of all page elements, including text and background,
should be controlled by CSS (not even by syntactically correct XHTML "style=" attributes).
Don't forget that fully-sighted readers still need sufficient contrast in both hue and
brightness in order to read the page.
- Sect 508, 1194.22(d) Documents shall be organized so they are readable without requiring an associated style sheet.
- WCAG 6.1 Organize documents so they may be read without style sheets. For example, when an HTML document is rendered without associated style sheets, it must still be possible to read the document.
- Beyond the checkpoint: Organize the document first, with no style sheet. Look at it
in plain XHTML and test it with a screen reader if necessary. If it makes sense this
way, then develop the style sheet, which can re-arrange elements on the page
for easier use by fully-sighted readers.
Image maps, server
- Sect 508, 1194.22(e) Redundant text links shall be provided for each active region of a server-side image map.
- WCAG 1.2 Provide redundant text links for each active region of a server-side image map.
- Beyond the checkpoint: There is probably no reason today to use a server-side image map,
despite the exception given in the checkpoint below.
Image maps, client
- Sect 508, 1194.22(f) Client-side image maps shall be provided instead of server-side image maps except where the regions cannot be defined with an available geometric shape.
- WCAG 9.1 Provide client-side image maps instead of server-side image maps except where the regions cannot be defined with an available geometric shape.
- Beyond the checkpoint: If the image map is only a graphic containing text, it
should be replaced with non-graphic text links. If it is truly graphic (for example,
a map of the United States for selecting a state), it should be supplemented by a
non-graphic input control (for example, a drop-down list of states).
- Sect 508, 1194.22(g) Row and column headers shall be identified for data tables.
- WCAG 5.1 For data tables, identify row and column headers.
- Beyond the checkpoint: Modern design uses tables for tabular data only, not
for layout. (Use CSS for layout instead.) Make sure that even with the required
headers, the table makes sense when linearized (read in order by a text reader).
- Sect 508, 1194.22(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.
- WCAG 5.2 For data tables that have two or more logical levels of row or column headers, use markup to associate data cells and header cells.
- Beyond the checkpoint: Complex tables are difficult to linearize sensibly;
in addition to using proper markup, look for simpler ways to present the data.
- Sect 508, 1194.22(i) Frames shall be titled with text that facilitates frame identification and navigation.
- WCAG 12.1 Title each frame to facilitate frame identification and navigation.
- Beyond the checkpoint: Frames are forbidden in XHTML 1.0 Strict and Transitional,
for good reason. Retrofit existing sites if necessary to meet this checkpoint; use
CSS to accomplish the same thing in new development.
- Sect 508, 1194.22(j) Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.
- WCAG 7.1 Until user agents allow users to control flickering, avoid causing the screen to flicker.
- Beyond the checkpoint: Flickering at the wrong rate may cause seizures, but it also irritates virtually all users, no matter what the frequency. Any motion
should be essential to the message of the page, not a distraction, and then of course
in compliance with this checkpoint.
- Sect 508, 1194.22(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.
- WCAG 11.4 If, after best efforts, you cannot create an accessible page, provide a link to an alternative page that uses W3C technologies, is accessible, has equivalent information (or functionality), and is updated as often as the inaccessible (original) page.
- Beyond the checkpoint: There should be no reason that a correctly organized page,
using proper separation of content and presentation, should ever need a separate
"text equivalent" page.
- Sect 508, 1194.22(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.
- WCAG 6.3 (not cross-referenced by Section 508) Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page.
- Beyond the checkpoint: Client-side scripts can provide real advantages for many
users, but may cause problems for others. Modern "unobtrusive" scripting techniques provide full content
with or without scripts and do not require browser detection or <noscript> elements. Thorough
testing on multiple platforms and with assistive technology is mandatory.
- Sect 508, 1194.22(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).
- WCAG 8.1 (not cross-referenced by Section 508) Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies.
- Beyond the checkpoint: The 1194.21 standards apply to software in general, so any
page that contains elements in this category will require additional evaluation and testing beyond
what is required for other web pages.
- Sect 508, 1194.22(n) When electronic forms are designed to be completed on-line, the form shall allow people using assistive technology to access the information, field elements, and functionality required for completion and submission of the form, including all directions and cues.
- WCAG 9.4 and 9.5 (not cross-referenced by Section 508) Create a logical tab order through links, form controls, and objects. Provide keyboard shortcuts to important links (including those in client-side image maps), form controls, and groups of form controls.
- Beyond the checkpoint: In general, each form input or group must have an associated <label>
element (not just plain text next to it); inputs may also be grouped with the <fieldset> element.
The tab order of input elements must be set in a logical sequence for use without a mouse.
- Sect 508, 1194.22(o) A method shall be provided that permits users to skip repetitive navigation links.
- WCAG 13.6 (not cross-referenced by Section 508) Group related links, identify the group (for user agents), and, until user agents do so, provide a way to bypass the group.
- Beyond the checkpoint: Both requirements are best accommodated by providing meaningful headings for
each group of links.
- Sect 508, 1194.22(p) When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.
- WCAG Guideline 7 (not cross-referenced by Section 508) Ensure user control of time-sensitive content changes.
- Beyond the checkpoint: Some timed-response scenarios (for example, an online examination) may require
off-line accommodation (for example administering the exam in a controlled but time-relaxed environment).