Although accessibility is related to the issues of usability and coding standards, it is possible for a site to be considered usable and standards compliant but NOT accessible.
Usability refers to the ability of average users with the "standard" range of equipment or abilities to navigate and use a Web site. In most cases, accessibility standards will also add usability to a Web site.
Web standards refer to initiative from the W3C Consortium and other Internet standards bodies to develop open Web standards which can be used by any software developer. The goals of standards is to ensure cross-platform compatibility and more compact file sizes. However, standards have also been developed for accessibility.
Although many accessibility guidelines are straightforward, some guidelines may conflict with usability or standards. For these cases, extra care must be taken to ensure that all audiences are able to access and use a Web site.
| Issue | Good Usability/Standards | Bad Accessibility | Solution |
|---|---|---|---|
| Color Coding | Color is a key visual signaling device for humans | BUT, about 10% of men are partially color blind and cannot distinguish certain colors (especially red/green) | Supplement color coding with text/icon coding |
| Acronyms & Compounds | Style conventions may require acronymns like HTML, PDF, NaCl, Sitemap, etc. to be listed without periods or spelled as one word | BUT, screen readers often mispronounce these items. | Include the ACRONYM tag to assist in pronunciation |
| Multimedia | Using images, sound and animations can often be more comprehensible than large blocks of text. Some people even recommend icons for users with some cognitive impairments. | BUT screen readers cannot interpret multimedia elements without textual assistance | Always implement ALT text, extended text descriptions and captioning or transcripts |
| Repetitive Navigation | Having navigation repeated on top and bottom is good for consistency and for some motion disorders. | BUT it is tedious for users of screen readers to hear the navigation on every page. | Implement "Skip Navigation" strategy |
| Multiple Columns | Multiple columns are one way to reduce text width to narrower widths conducive for legibility and include more material in one screen | BUT multiple columns are difficult for some screen readers to interpret. | You can use style sheets to reduce a column width
within a single-column layout. Use appropriate table tags for data tables and make sure layout tables make sense when read left to right, top to bottom. |
| Unicode for Foreign Languages | Unicode makes data exchange between operating systems and foreign languages easier | BUT some screen readers cannot recognize Unicode input | Consult with users for best solutions. Audio files may be needed for some items. |
| PDF Files | PDF may be the only way to present information in complicated layouts or with unusual symbols online for all browsers. | Screen readers may not be able to interpret all the information | PDF files need to be made accessible just as Web pages are. |
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