function resizeMainBody() {
	$('mainbody').style.overflow = "auto";
	var height = document.viewport.getHeight() - ($('header').getHeight() + $('top-navigation').getHeight() + $('footer').getHeight());
	
	if (height < $('navigation').getHeight()) height = $('navigation').getHeight();
	
	height -= 25;
	
	$('mainbody').style.height = height + "px";
	
//	alert($('footer').cumulativeOffset().top + " / " + $('footer').getHeight() + " / " + document.viewport.getHeight());
}