function checkSystemTime(servertime,msg)
{
    var date_syst = new Date();
    var date_serv = new Date();
    var ourtime = servertime;

    date_serv.setTime(ourtime*1000);

    var date_diff = (date_syst.getTime()/1000) - (date_serv.getTime()/1000);
    var date_comp1 = (60 * 60) * 24;
    var date_comp2 = (60 * 60) * 24 * (-1);

    if (date_diff > date_comp1 || date_diff < date_comp2) {
        alert(msg);
        return false;
    }

    return true;
}