JavaScript functional testing using selenium
Currently we found that current selenium can actually be used to test the functionality of javascript. Check the ajax testing demo: http://www.openqa.org/selenium-core/demos.html. You will find selenium can be used to test the drag and drop and other ajax effects.
The recently added css selector locator can be used to test the order of HTML elements by using the pseudo class selectors as you saw in the demo. The drag and drop command works well in the Firefox, IE and Opera.
Based on selenium, jsunit, we actually can develop javascript application in a TDD way. There are still some cross browser bugs and usability of some commands are not so good, but we are trying to improve it.