[Greasemonkey] Finding Mouse Coordinates

[Brendan Crosser-McGay]

On this script: http://userscripts.org/scripts/show/1434

In the script for making a transparent draggable window, I need the mouse
event to be able to drag it around properly.  The only place I've found the
mousex and mousey values seem to be inside that event.  My dilemma is, I
want a link on the page that will reposition this draggable window element
to the exact place where the mouse is, which is right at the link.

The only half-usable solution I've managed to come up with, is one where on
the click, it reinitializes the entire window at the mouse position, but it
still requires the mouse to be moved before the element actually changes
coordinates.

Thanks,
Brendan