CSS 100% height with padding/margin
- by Toji
This has been driving me crazy for a couple of days now, but in reality it's a problem that I've hit off and on for the last few years: With HTML/CSS how can I make an element that has a width and/or height that is 100% of it's parent element and still has proper padding or margins?
By "proper" I mean that if my parent element is 200px tall and I specify 100% height with 5px padding I would expect that I should get a 190px high element with 5px "border" on all sides, nicely centered in the parent element.
Now, I know that that's not how the standard box model specifies it should work (although I'd like to know why, exactly...), so the obvious answer doesn't work:
#myDiv {
width: 100%
height: 100%;
padding: 5px;
}
But it would seem to me that there must be SOME way of reliably producing this effect for a parent of arbitrary size. Does anyone know of a way of accomplishing this (seemingly simple) task?
Oh, and for the record I'm not terribly interested in IE compatibility so that should (hopefully) make things a bit easier.
EDIT: Since an example was asked for, here's the simplest one I can think of:
<html style="height: 100%">
<body style="height: 100%">
<div style="background-color: black; height: 100%; padding: 25px"></div>
</body>
</html>
The challenge is then to get the black box to show up with a 25 pixel padding on all edges without the page growing big enough to require scrollbars.
