var win;//NEW

function popup(url, name, w, h)
{
    var winl = (screen.width - w) / 2;
    var wint = (screen.height - h) / 2;
    winprops = 'height=' + h + ',width=' + w + ',top=' + wint + ',left=' + winl + ',toolbar=0,scrollbars,location=0,statusbar=0,menubar=0,resizable,';
    win = window.open(url, name, winprops);
       win.focus();
}