Question

jsfiddle – As you can see, all divs heights are given in pixel (div a and div b). Last one (div c)has height:100%, so its as high as all the body. I want it just to fill its parent, not to be as high as all the document. (yellow div is overflowing).

Answer 1

div#b {
    float: left;
    width: 100%;
}

this does the trick

http://www.jsfiddle.net/KWZdD/30/