Constructor facade for JQueryEventObject. See the documentation of the JQueryEventObject trait for more
information about the various constructor methods.
TBD: does this need to use jsext? Possibly not. Look at this more closely, and see if switching to a more
straightforward constructor is more appropriate in this case. If all of the parameters are singly-typed,
then jsext is overkill.
In general, this is rather half-baked, and needs enhancement and sanity-checking.