calc()

calculation in css3

by toubia95

HTML

<div id="foo">Always 100 pixels less than half the available area</div>

CSS

#foo { 
    background:silver;
    /*width: 50%; */           
    width: -moz-calc(50% - 100px);
    width: -webkit-calc(50% - 100px);
    width: calc(50% - 100px);
}