[Javascript] Resize INNER window

[Thierry Lavall=?ISO-8859-1?B?6Q==?=e]

Hi,
I would like the INNER part of the window (the body) to resize to fixed
values (ex: 400,600).

Is there a JS that would help me achieve this? The only ones I found resize
the total window while what I care about is that the content shows
completely to the values I set for inner. without scroll bars and all body
showing.

Thanks!
-- 
Thierry