function verticalAlign() {
	var divMain = document.getElementById("DivMain");
	var offsetHeight = 578;
	var marginTop = (document.documentElement.clientHeight - offsetHeight) / 2;
	if (marginTop > 0) {
		divMain.style.marginTop = marginTop + "px";
	}
	divMain.style.display = "block";
}

window.onresize = verticalAlign;