function getHeightforbg() {
	var pageHeight = document.getElementById('page').offsetHeight/16;
	var lefttopHeight = document.getElementById('top').offsetHeight/16;
	var righttopheight = document.getElementById('top').offsetHeight/16;
	var newleftHeight = pageHeight - lefttopHeight;
	document.getElementById('leftwrap').style.height = newleftHeight+"em";
	var newrightHeight = pageHeight - righttopheight;
	document.getElementById('rightwrap').style.height = newrightHeight+"em";
}