var NS = (document.layers);
var IE = (document.all);
var popup
if (IE) 
{
popup = null;
}
function new_window(s,w,h) 
{
var w=w+0;
var h=h+0;
var halfWidth = ((screen.width / 2) - (w / 2));
var halfHeight = ((screen.height / 2) - (h / 2));
if (NS)
{
popup = null;
}
if (popup != null && !popup.closed)
{ 
popup.close();
}

popup =
window.open(s,'popup','toolbar=no,title=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,width=' + w + ',height=' + h + ',top=' + halfHeight + ', left=' + halfWidth + '');
popup.focus();
}