function popupWindow(url)
{
	windowName="popup";
	width=400;
	height=300;
	x=(screen.availWidth - width)/2;
	y=(screen.availHeight - height)/2;
	var str="directories=no,location=no,resizable=no,scrollbars=yes,status=no,toolbar=no,width=" + width + ",height=" + height+",left="+x+",top="+y;
	win = window.open(url, windowName, str);
	win.window.focus();
}