I got back this week from the OpenACS/.LRN conference in Guatemala. There was a great bunch of interesting people there and there was a lot to learn.

I presented on an AJAX-enhanced data table, known in OpenACS as Listbuilder. The video and slides are available. The user interface was inspired by DabbleDB, which provides a collaborative alternative to spreadsheets for managing data. In our case, we needed to integrate this level of interactive data manipulation with an existing .LRN system. Data privacy was also an issue, so everything must be hosted internally. 

We followed, for the most part, the concept of progressive enhancement. This allows the features to be available even if Javascript is not enabled in the browser. The goal is to create a fully functional, semantic HTML page, then add additional behaviors with Javascript. The Yahoo UI library is ideal for this type of application. It makes it easy to add behaviors based on CSS class or ID.

Another key issue in making accessible Web applications is page updates. Currently, no assistive technology can consistently notify the user if a page element has changed unless the page is reloaded. For this we reload the page on every change instead of just updating part of the page with background AJAX calls.

We also worked hard to make sure that any existing listbuilder list within OpenACS could use this added behavior. There is still some work to do in this area before we release the code.

A demo of the functionality is available .