onload = function(){
	bannerSet();
}

function bannerSet(){
	boxH = document.getElementById('box').offsetHeight;
	sideH = document.getElementById('side-box').offsetHeight;
	bannerH = document.getElementById('minus6').offsetHeight;
	
	marginSet = boxH - (sideH + bannerH) - 8;
	
	if(marginSet <= 0){
		document.getElementById('minus6').style.marginTop = marginSet + 8 + 'px';
	}else{
		document.getElementById('minus6').style.marginTop = marginSet + 'px';
	}
}