CSS - Height of 100% minus #px - Header and Footer

Question

The webpage in question looks like this:

// The Header //
/*            */
/*  CONTENT   */
/*            */
// The footer //

Both the head

Answer 1

If your browser supports CSS3, try using the CSS element Calc()

height: calc(100% - 65px);

you might also want to adding browser compatibility options:

height: -o-calc(100% - 65px); /* opera */
height: -webkit-calc(100% - 65px); /* google, safari */
height: -moz-calc(100% - 65px); /* firefox */