function excel_time($date, $time = false) {
    if (function_exists('GregorianToJD')) {
        if (is_numeric($date)) {
            $jd = GregorianToJD(1, 1, 1970);
            $gregorian = JDToGregorian($jd +intval($date) - 25569);
            $date = explode('/', $gregorian);
            $date_str = str_pad($date[2], 4, '0', STR_PAD_LEFT) .
            "-" . str_pad($date[0], 2, '0', STR_PAD_LEFT) .
            "-" . str_pad($date[1], 2, '0', STR_PAD_LEFT) . ($time ? " 00:00:00" : '');
            return $date_str;
        }
    } else {
        $date = $date > 25568 ? $date +1 : 25569;
        /*There was a bug if Converting date before 1-1-1970 (tstamp 0)*/
        $ofs = (70 * 365 + 17 + 2) * 86400;
        $date = date("Y-m-d", ($date * 86400) - $ofs) . ($time ? " 00:00:00" : '');
    }
    return $date;
}