function getWindowHeight(){
		return document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.offsetHeight;
	}
function setTopMargin(){	
	var tempHeight = getWindowHeight();
	tempHeight = (tempHeight > 600) ? Math.floor((tempHeight - 600) / 2) : 0;
	tempElement = document.getElementById('topMargin');
	tempElement.style ? tempElement.style.margin = tempHeight + "px" : tempElement.padding = tempHeight;
}