CSS: Setting width/height as Percentage minus pixels

Question

Hi all,

I've seen this question asked in a couple other contexts on SO, but I thought it would be worth asking again for my particular case. I'm trying to create some re-usable CSS classes for more consistency and less clutter on my site, and I'm stuck on trying to standardize one thing I use frequently.

I have a container div that I don't want to set the height for (because it will vary depending on where on the site it is), and inside it is a header div, and then an unordered list of items, all with CSS applied to them. It looks a lot like this:

I want the unordered list to take up the remaining room in the container div, knowing that the header div is 18px tall. I just don't know how to specify the list's height as "the result of 100% minus 18px". Does anyone have any advice in this situation?

Thanks very much.

Answer 1

I use Jquery for this

function setSizes() {
   var containerHeight = $("#listContainer").height();
   $("#myList").height(containerHeight - 18);
}

then I bind the window resize to recalc it whenever the browser window is resized (if container's size changed with window resize)

$(window).resize(function() { setSizes(); });

Answer 2

Presuming 17px header height

List css:

height: 100%;
padding-top: 17px;

Header css:

height: 17px;
float: left;
width: 100%;

Answer 3

I'm not sure if this work in your particular situation, but I've found that padding on the inside div will push content around inside of a div if the containing div is a fixed size. You would have to either float or absolutely position your header element, but otherwise, I haven't tried this for variable size divs.