function newWindow(url, w, h, useScroll) 
{
    var settings = 'location=no,directories=no,menubar=no,toolbar=no,resizable=no,';
    settings += 'scrollbars=' + ((useScroll == true || useScroll > 0) ? 'yes' : 'no') + ',';
    settings += 'width=' + w + ',height=' + h + ',top=' + ((screen.height - h) / 2) + ',left=' + ((screen.width - w) / 2);
    var win = window.open(url, '', settings);
    win.window.focus();
    return win;
}