One possible partial work-around is to separate the testing of the fundamental request/response data versus testing the rendered result itself. For example, if you are using
Struts then MockStrutsTestCase can be used to see if the data about to be send to the
JSP page and the selected forwarding is what you expect. That tells you if everything prior to the final rendering is at least correct.
For Javascript-specific testing, there are I think three derivations of
JUnit out there, but really they are only helpful for letting you test a Javascript library, not so much a specific page. I haven't seen anything that combined HttpUnit-like testing of the rendered result with Javascript either.