your pop-up takes a while to load (for whatever
reason) or if another pop-up from another site
(which your visitor is browsing simultaneously)
pops up, then your pop-up may get pushed to the
background - which is not a good thing, because
out-of-sight is out-of-mind.
this script at the very end of your pop-up page,
will make your pop-up spring back to life even
if the user had minimized it.
course, if your visitor closed it before it could
load, then there is nothing we can do about it.
But for some reason, if your pop-up got over-shadowed,
then this script will make sure it comes back
to focus the moment it has finished loading.
only that, once it has come back into focus, it
will keep coming back again and again, till the
user takes some action (like submitting a form,
or closing the pop-up itself).
this script smartly and judiciously, because it
can tend to get annoying if you don't let the
user minimize the window.