JSFUnit should work perfectly fine with AJAX-enabled applications.  This is because we rely on HTMLUnit to act as a "headless browser".  So anytime a browser event (like onchange or onclick) is fired, the corresponding javascript will run and any AJAX processing will take place.  However, HTMLUnit is not perfect in this regard.  It is the best pure java headless browser out there, and it is improving all the time.

If you do have problems with AJAX and/or javascript execution, please report it on the JSFUnit Forum or report it directly to the HTMLUnit project.