Yeah, I'd like this too.. I'm sure the HTML editor nukes Javascript input as a security measure. However this is also inspiring me to find ugly solutions that I can just see leading to pain later. What would work best for me is a WYSIWYG that will allow javascript editing for certain users and notifies others if they're editing a page without javascript editing permission (and thus will cause the javascript to be disabled upon saving their edits).
But for now, I'll do the hacky thing..