Window Resize To Required Size

A dynamically created html page contains a body tag with a single (filled)
table in it. Sie size of the table changes in a wide scale (from 5% to 150%
of the screen size independent in height and width.
The page is displayed in a popup window opened either via an onclick-event
or a href anchor (depends on the navigation). Now the obvious problem is
this:
When choosing a fixed window size things look silly most of the time. Either
you have a nearly empty window or you have to scroll all the time...

So I want to resize the window. Resize it to what size? The size that is
required by the pages content when redered in the browser. That's all :-)

-- hmmm -- I tried around quite a lot with scrollHeigths, offsetWidth and so
on, but there does not seem to be any more or less reliable solution.,
Especially not when trying to make stuff usable for different browsers.
Does anyone have a hint what else I can try, where I could look?