function popWindow(url, myname, w, h)
{
   var padding;
   (navigator.appName == "Microsoft Internet Explorer") ? (padding = 10) : (padding = 0);
   var screenw = screen.availWidth;
   var screenh = screen.availHeight;
   var winw = (w + 15 + padding);
   var winh = (h + 15 + padding);
   var posx = (screenw / 2) - (winw / 2);
   var posy = (screenh / 2) - (winh / 2);
   var mywin=window.open(url,myname,"top="+posy+",left="+posx+",width="+winw+",height="+winh+",menubar=no, locationbar=no, statusbar=no, resizable=no, toolbar=no, dependent=yes, scrollbars=yes");
   mywin.focus();
}