AJAX and DHTML have made web sites more interactive and easier to use. At least for visitors who are not using a screen reader. Screen reader users have to struggle with pages that lose focus, change without prompting the user of new data, and much more. However, there are many developers working on solutions to this problem.
Here’s how Todd describes the goal
The YUI TabView Control is built on a strong
foundation of semantic markup that provides users with some basic accessibility. But while TabView looks like a desktop tab control, screen readers don’t present it as an atomic
widget, leaving users to figure out how the various HTML elements that compose a TabView relate to each other. However, through the application of the WAI-ARIA Roles and States, it is possible to enhance TabView’s accessibility such that users of screen readers perceive it as a desktop tab control.
Enhancing TabView Accessibility with WAI-ARIA Roles and States – Todd Kloots
The following video shows how this approach works with Firefox and a screen reader.
Bill Scott gave an interesting lecture today at Yahoo! about AJAX design patterns. He explained how good AJAX designs keep the user’s attention on the page, remove roadblocks, and increase stickiness to a site.
Patterns of successful AJAX behaviors are beginning to appear (Netflix, 37Signals, Yahoo!). There are subtle, and sometimes not so subtle, changes that can occur to let a user know that an action has happened.
Download the drag and drop storyboard design package
For instance, he pointed out an interaction on the recently departed Yahoo! Photos site. A user could select multiple photos and then drag them to special collection folders. The page generated several panels to let the user know that the move would go to the preferred folder (hit yes), wait for the action to finish, and then a final congratulations panel (hit yes). These panels and the two required clicks could have been avoided if the folder changed when the photos were dropped into it. This could be a simple glow and maybe the number of photos in the folder is increased.
Plan your entire sequence in advance
Eric Miraglia coined the phrase Interesting Moments to describe the multiple changes that occur during an AJAX/DHTML action.
In most cases, Drag and Drop requires that you write code to respond to the interesting moments in the interaction: when the drag event starts, when the dragged object enters another object, and so on.
Yahoo! UI Library: Drag & Drop – Interesting Moments
Your user will have a much more pleasant experience if these are considered in the beginning of production. The Yahoo User Interface library includes a storyboard template (.zip) for planning these interactions effectively. This story board concept also works well for forms (especially form validation actions) and Flash components.
The YUI blog has posted a video of Bill’s lecture: YUI Theater — Bill Scott: “Designing the Rich Web Experience: Principals and Patterns for Rich Interaction Design on the Web”. This is a great opportunity to learn from one of the finest developers around.