This program can help check documents for compliance with certain parts of US Section 508 federal requirements.

NOTE: In early 2017, the United States Access Board updated Section 508 to measure accessibility compliance against the more modern and internationally recognized WCAG 2.0 AA standard. The Section 508 checking here is currently based on the older guidelines and requirements. We recommend checking documents with WCAG 2.0 AA (or better) checking enabled. This checking can be enabled in the WCAG Page.

Section 508 Checking Options

Enable US Section 508 federal standards accessibility checking - Check this box to enable accessibility messages based on pre-2017 US Government Section 508 Accessibility Standards (new window). This option has no effect if the Enable accessibility checking option is not checked. This option is not enabled by default.

Enable WCAG 2.0 AA Checking - Press this button to make sure that WCAG 2.0 AA checking is enabled to help comply with the 2017 update of Section 508 (the appropriate settings will be applied to the accessibility options). (New v18.00)

About Section 508 Accessibility

CSS HTML Validator can help check documents for compliance (but it cannot guarantee total compliance) with pre-2017 US government Section 508 accessibility requirements, specifically subpart B 1194.22 for web-based intranet and internet information and applications. Below is section 1194.22 (a)-(p):

(a) A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content).

(b) Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.

(c) Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup.

(d) Documents shall be organized so they are readable without requiring an associated style sheet.

(e) Redundant text links shall be provided for each active region of a server-side image map.

(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.

(g) Row and column headers shall be identified for data tables.

(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.

(i) Frames shall be titled with text that facilitates frame identification and navigation.

(j) Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.

(k) A text-only page, with equivalent information or functionality, shall be provided to make a website 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.

(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.

(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).

(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.

(o) A method shall be provided that permits users to skip repetitive navigation links.

(p) When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.

CSS HTML Validator includes validator messages to help comply with (a), (e), (f), (g), (h), and (i). Please note that complying with the validator messages is still no guarantee that a page is in full compliance. Full compliance with Section 508 accessibility requirements cannot be checked solely by a computer and requires human judgment.