function openPopup(url,width,height) {
    
	if (typeof(width) == "undefined") {
		var width = "600";
	}
	
	if (typeof(height) == "undefined") {
		var height = "500";
	}
	var screenY = screen.height;
	var screenX = screen.width;
	var topvar = (screenY - height) / 2;
	var leftvar = (screenX - width) / 2;
	
			
	var win = window.open(url,'','resizable=yes,scrollbars=yes,toolbar=no,menubar=no,location=no,status=yes,top='+topvar+',left='+leftvar+',width='+width+',height='+height+'');
	win.focus();
	return false;
}