var d = document;
var cLeft = d.getElementById('left');
var cRight = d.getElementById('right');
var cCenter = d.getElementById('center');
if (cLeft.offsetHeight > cRight.offsetHeight) {
	cRight.style.height = cLeft.offsetHeight-40+'px';
	cCenter.style.height = cLeft.offsetHeight+'px';
}
else {
	cLeft.style.height = cRight.offsetHeight-20+'px';
	cCenter.style.height = cRight.offsetHeight+'px';
}