However well that's supported over sticking with DOM 3, as I go back to this code, I feel it just doesn't work well enough even as-is.  Yes, the event listeners catch all the dispatched events, but the content attributes don't, and (it seems) not just because they don't work properly (or in time - in the next version, I add some lagtime for the tests to run in the next version, which helps the success rate, but not enough).  For example, "blur" does not get into the results array despite the dispatched event and plenty of time to register it, but then later, as I actually physically change the focus of the window back and forth and then check on the results array via the console, that content attribute finally registers in the results array.  I'm thinking to write the tests with more physical (but hopefully still automated) versions of event-causing rather than relying on new Events however they may be created/dispatched.  Has this kind of event-causing code already been done, though, and if so, might I be able to re-use that code?