Height Of A Page

I need to know the height of the *page,* not the viewport. So if I've
got a page that is like twice or three times the height of the viewport,
does anyone know of any way to calculate that using JS?

It's a nutty idea I suppose, but here's the backstory: I have a client
who has a site whose content is being generated by some crappy database
software he is pretty much married to. The site looks like the Web era
1994, and he wants to give it a facelift, but get this -- he doesn't
want to change the css stylesheet that the database company is supplying
him with, because everytime they issue an update to their software,
there's a new stylesheet, and he doesn't want to have to integrate their
changes into whatever stylesheet he's using. Whatever.

So I mulled this over for a while and suggested that we put the db crap
into an iframe and then surround it with a nice, well-designed margin
that matches that of the larger institution. Far from perfect, but I
thought it was a pretty good idea. Unfortunately he says the iframe
can't have a scrollbar -- it has to fit all the content of the page.

So I made the iframe really big, and his response: oh, but it has all
this ugly whitespace at the bottom.

Long story short (too late), I have to figure a way to adjust the height
of the iframe on the fly. I've got no idea if this is humanly possible.

Any clever ideas?