For 100% height to work you need to give the parent containers this height as well: CSS
overflow: auto; /* to prevent the body from appearing below the iframes */
But the height also includes the menu, etc., so the iframes will probably stretch beyond the browser viewport.
You could consider just giving the iframes a specific height and allowing scrollbars to appear.
: You may need to set the iframe heights to 100% using CSS or the style attribute.