//opens a window and centers it
    function openWin(sPage, w, h, scrollbars, status, resize, title) {
        var winL = (screen.width - w) / 2;
        var winT = (screen.height - h) / 2;

        var myWin = window.open(sPage, '', 'height=' + h + ',width=' + w + ',left=' + winL + ',top=' + winT + ',status=' + status + ',scrollbars=' + scrollbars + ',resizable=' + resize);

        return myWin;
    }