Emar, then you'll have to tell people to use a monitor with x dimensions. Monitors and screens come in many different shapes, which makes it unfortunate that CSS lets us easily compute widths based on browser width but not heights. Bleh. The Winblows machine at work has a mostly square-ish screen with 1024 resolution... but both my laptop and my colleague's 2" screen are very rectangular... I can't even properly set my computer's resolution to 600x800, because things have to stretch on my wider screen.
You can try to go for a "most common middle" to make the page look mostly okay on many screens. But for instance, my screen is 17" and is sitting at 1460x9-hundred-something right now. But when viewing a friend's page built for my screen size and rez settings, I could not see the bottom of his page without scrolling. Why? Because I was using Firefox, where I have the Web Developer Toolbar under my address bar, and then on the bottom I have a bar that states scripts have been blocked. That eats up a total of around 300 pixels or so of height.
so it mean i should let the height in % so its dependant of resize of the window or on tool bar.
Unfortunately, CSS doesn't set heights like that. If you set a % height on a box whose parent doesn't have an explicit (non %) height, then its height will become "auto", which means "the height of the content inside".
This does not work:
but this does:
There are tricks for getting 100% high pages, and that might be what you're after... why don't you check out the CSS FAQ sticky in Design area? The first post has a bunch of common things people ask for, and one of them is 100% height. It also depends on your design, but mostly, you'll have to try to think of a way to "fake" it, because you only get one chance at 100% height: only one element can do that if you're using the 100% height technique (well, unless you use the absolutely-positioned columns trick, which needs fixing in IE6). See what you can fake first.