function openWindow(url, 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,"mywin","top="+posy+",left="+posx+",width="+winw+",height="+winh+",menubar=no,locationbar=no,statusbar=no,resizable=no,toolbar=no,dependent=yes,scrollbars=no"); 
   mywin.focus(); 
}