function setTall() {
	if (document.getElementById) {
		var divs = new Array(document.getElementById('nav'), document.getElementById('content'), document.getElementById('ad'));
		
		var maxHeight = 0;
		for (var i = 0; i < divs.length; i++) {
			if (divs[i].offsetHeight > maxHeight) maxHeight = divs[i].offsetHeight;
		}
		
		for (var i = 0; i < divs.length; i++) {
			divs[i].style.height = maxHeight + 'px';

			if (divs[i].offsetHeight > maxHeight) {
				divs[i].style.height = (maxHeight - (divs[i].offsetHeight - maxHeight)) + 'px';
			}
		}
	}
}

window.onload = function() {
	setTall();
}

window.onresize = function() {
	setTall();
}