Accessibility: Why is it important?
Imagine you go to the store to buy a birthday gift for your friend. You walk in the store and the appearance of the store immediately impresses you. Everything is clean. There is nice music playing faintly in the background. There is a pleasant scent in the air. As you begin to browse the aisles, though, you notice something is amiss. You cannot find what you're looking for. The aisles are not labeled well. They are also a bit narrow and you keep bumping into people. There are no store employees in sight to help you. What would you do? After a time of looking around in vain, you would leave the store and decide to shop somewhere else.
-- Michael Stalker
Websites are much like the example above, but with some extra effort, the overall accessibility and usability of your website can dramatically increase. The easiest ones to implement include writing alt tags for images, defining more parts of data tables, and providing well-structured web pages that can be understood easily by search engines and screen readers. Read the Section 508 guidelines below for more information.
Section 508 Standards
§1194.22 Web-based intranet and internet information and applications
A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content).
Alt tags ('alternate text') provide a clue to a screen reader or search engine of the subject of the image it is applied to. For instance, adding a description "Students studying by Renne Library" will allow the user to envision students studying by the library. Additionally, a person searching for images in a search engine could type "Renne Library" and this image may be one of the results. Alternately, if no alt tag was provided, or a description of the image was very generic, i.e. "students image", the user would have a more difficult time understanding what the picture is for.
Documents shall be organized so they are readable without requiring an associated style sheet.
When possible, use tags such as <strong> and <em>, as well as paragraphs and lists to construct your web page. Group similar items within the same div container, if necessary.
Row and column headers shall be identified for data tables.
If constructing a table containing data, adding headers (<th>) will help a user understand the table more completely. Along with headers, one can add scope, captions, summaries and abbreviations to parts of their tables to make them more logical. To read more visit webusability's Accessible Data Tables guide.
Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.
Web pages shall be designed so that all information conveyed with color is also available without color, for example from context or markup.
Redundant text links shall be provided for each active region of a server-side image map.
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.
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.
Frames shall be titled with text that facilitates frame identification and navigation.
Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.
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 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.
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).
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.
A method shall be provided that permits users to skip repetitive navigation links.
When a timed response is required, the user shall be alerted and given sufficient time to indicate more time is required.
Resources for Accessible Design
- webusability's Accessible Data Tables
- Color Filter Check
- Color Contrast Check - snook.ca
- WAVE - web accessibility evaluation tool
- 2010 ADA Standards for Accessible Design