var cheight = document.getElementById('content').offsetHeight;
var lbheight = document.getElementById('leftBlock').offsetHeight;
var maindiv = document.getElementById('main');
var mheight = maindiv.offsetHeight;
if (cheight > lbheight){
	newheight = cheight + 25;
}
else{
	newheight = lbheight +25;
}
if (mheight < newheight){
	maindiv.style.height = newheight + 'px';
}