function openWindow(url, n, w, h, xpos, ypos) {
xpos = (screen.width-w)/2
ypos = (screen.height-h)/2
var windowprops = "toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=yes,resizable=yes,,width=" + w +",height=" + h +",left=" + xpos +",top="+ ypos;
var windowname = n
popup = window.open(url,windowname,windowprops);

}