A presentation by Derek Featherstone
[Derek waves his arms and steadfastly refeses to use the phrase “web 2.0”!]
Derek is an accessibility expert who is trying to get the message across that, even in a web2.0 world, accessibility should still be a goal, and and achievable one.
The web now is moving towards functionality and applications, and away from the document-centric approach. To make apps accessible, it is vital to separate the app into three distinct areas:
- Content (eg semantic, standards-compliant XHTML)
- Presentation (CSS does all the hard work)
Similarly, validation error messages should always appear near the form control they validate. If you put it at the top of a page, and a user has the screen hugely magnified, they will never see the error text as it’s well out of their portion of the viewport. Perhaps changing the background colour of an element which fails validation could also be useful.
So if it’s easy to get such simple things wrong, what about applications using AJAX which can be very complex? The answer is, wherever possible, to try and make the content linearised within the page by setting tab orders etc to “lead” users through their application journey in a sensible way.
Tabindex=”-1″ might sound like an invalid value, but it is supported by IE and Firefox. It can be programmatically, as it does not show up in a tab set, but you can use it to force focus onto an element.
Drag and Drop interactions are great for the mouse-enabled community, but pretty hopeless for those only using a keyboard. So don’t make it the ONLY way of doing something. Also, make the “hit area” of links or things to drag as large as possible, so that users with impaired mobility don’t have to be so accurate with their mouse movements.