How To Be Accessible

Two closely related efforts are underway to provide guidelines on accessible Web design - the Federal government's Section 508 initiative and the World Wide Web Consortium's Web Accessibility Initiative.

The following table summarizes the two sets of guidelines.

Accessible Design Practice Section 508
Structure Your Content Properly And Use Stylesheets
Use HTML logically to structure your content. For example, use header elements to show the logical relationship of the headers - h1's as main topics, h2's as subtopics, h3's as subsubtopics, and so on. Then control presentation aspects like font style and background color with stylesheets. If done properly, your page should be easily readable even without the stylesheet.
(d) Readability(style sheets) Guideline 3: Use markup and style sheets and do so properly
Provide text describing every non-text element.
Using "alt" and "longdesc" attributes, provide text explaining each image, java applet, or other non-text element. Where an image contains essential information, either provide descriptive text or link to a text-only page that provides the same information in text form.
(a) A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content). Guideline 1. Provide equivalent alternatives to auditory and visual content.
With multimedia files, provide captioning or audio description of visual information
Audio files should have nearby links to text transcriptions. Video files should be close captioned except where synchronization is unnecessary. In general, make use of available accessibility improving features in the media you are using.
(b) Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation. Guideline 1. Provide equivalent alternatives to auditory and visual content.
Don't Rely On Color Alone
Avoid using color alone to convey information, such as using red to indentify warnings and green to identify recommended practices. The text should explain itself.
(c) Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup. Guideline 2. Don't rely on color alone.
Design your tables to read ("linearize") well and label them to help associate each table cell with row and column headers.
Voice browsers generally read a table by progressing cell by cell across each row, starting with the top row. A two-dimension table is thus reduced to a linear series of pieces of text. Design your tables so they will make sense when read (heard) this way. Use THEAD, TFOOT, and TBODY to group rows, COL and COLGROUP to group columns, and the "axis", "scope", and "headers" attributes, to describe more complex relationships among data.
(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.
Guideline 5. Create tables that transform gracefully.
Preferably, avoid frames. If you do use frames, clearly establish the content of each pane in the layout with text in the title and in the body of the page.
Because frames layouts display more than one page at the same time, they are inherently problematic for persons using adaptive technology. It is easy for a disabled person to lose track of which page he or she is viewing. When using frames, give each frameset a title and give each page an explanatory text in the body.
(i) Frames shall be titled with text that facilitates frame identification and navigation. Guideline 6. Ensure that pages featuring new technologies transform gracefully.
Guideline 12. Provide context and orientation information.
Label fields in online forms to make it clear what information should be entered in each field.
Forms can be challenging for persons using adaptive technologies. The text describing a particular form field might occur anywhere near the field (above, below, left, right) depending on the page design. To make sure a person hearing the page knows what information to enter in the field, use a Label element to enclose the describing text and an ID attribute in the Input element.
(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. Guideline 8. Ensure direct accessibility of embedded user interfaces.
Provide descriptive text for each image map "hot spot."
Provide "alt" text for each area defined in an image map describing where the hot spot is linked to. Use client-side image maps. In general, avoid server-side image maps
(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.
Guideline 1. Provide equivalent alternatives to auditory and visual content.
Label links to scripts and carefully evaluate how the script will function with adaptive technologies
Scripts evoked by means of an anchored link should have descriptive link text. Where an image is used in the anchored link, provide "alt" text. Carefully select the event handlers (onmouseover, onclick, etc.) you use to be sure they will work for persons using adaptive technology
(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. Guideline 6. Ensure that pages featuring new technologies transform gracefully.
If all else fails, provide alternative text-only pages
Where essential information cannot be made accessible otherwise, provide text-only alternatives with the same content and functionality.
(k) A text-only page, with equivalent information or functionality, shall be provided to make a web site comply with the provisions of these standards, when compliance cannot be accomplished in any other way. The content of the text-only page shall be updated whenever the primary page changes.  

Other Practices That Help

  • When linking to files that require plug-ins, provide a link to where the plug-in can be obtained.
    Proprietary formats like Adobe Acrobat PDF files, which can be created with accessibility features, require plug-ins since browsers do not know how to display them.
  • Define abbreviations
    Enclose abbreviations and acronyms with "abbr" and "acronym" elements with "title" attributes giving the full expansion.
  • Identify TTY and Phone numbers
    Phone numbers listed on Web pages should be identified as voice, TTY, or both. FAX numbers should be clearly labelled as such.
  • Provide a way to skip repetitive navigation links
    Often, page designs have lengthy menus at the beginning or end of each page. To person using adaptive technology, having to tab through such menus to get to the content can be time consuming. Project a link to jump from near the top of the page directly to the content.
  • Avoid flicker
    For some people, flicker rates between about 2 Hz and 55 Hz have the potential to be hypnotic or to evoke seizures. Animated gifs, scripts, and applets should have relatively slow motion, particularly if bright. Having the flicker or motion stop after a few cycles also is desirable.
  • If response within a limited time is required, alert the user and give them a way to get more time
    A window that goes away or redirects after a limited time can be frustrating to someone slowly reading the page, especially if the page is a form they are trying to fill out.


Using Web Publishing Software

Checking Your Pages

Accessible Media

Vendor Accessibility Sites