function popup (fileName, name, width, height) {
if (document.all || document.layers) {
	var screenW = screen.availWidth;
	var screenH = screen.availHeight;
}
var left = (screenW - width) / 2;
var top = (screenH - height) / 2;
var props = "width=" + width + ",height=" + height + ",scrollbars=yes,menubar=no,directories=no,resizable=yes,toolbar=no,status=no,left=" + left + ",top=" + top + "";
	popupWindow = window.open(fileName, name, props);
	popupWindow.focus();
}