function setCenter(){
	var d = document.getElementById("main");
	var wH = document.documentElement.clientHeight;
	var wW = document.documentElement.clientWidth;
	var dH = d.clientHeight;
	var dW = d.clientWidth;
	var t = wH/2-dH/2;
	var l = wW/2-dW/2;
	d.style.top = t+"px";
	d.style.left = l+"px";


}

window.onload= function(){
	setCenter();
}
window.onresize= function(){
	setCenter();
}