css float - CSS container div not getting height

Question

I want my container div to get the height of max of its children's height. without knowing what height the child divs are going to have. I was trying out on JSFiddle. The container div is on red. which is not showing up. Why?

Answer 1

Add the following property:

.c{
    ...
    overflow: hidden;
}

This will force the container to respect the height of all elements within it, regardless of floating elements.
http://jsfiddle.net/gtdfY/3/

UPDATE

Recently, I was working on a project that required this trick, but needed to allow overflow to show, so instead, you can use a pseudo-element to clear your floats, effectively achieving the same effect while allowing overflow on all elements.

.c:after{
    clear: both;
    content: "";
    display: block;
}

http://jsfiddle.net/gtdfY/368/