How Do I Force A User To Logout After The Timer Ends?

<script language="javascript" type="text/javascript">
    //Session timeout in minute.
    var sessionTimeout = "<%= Session.Timeout %>";

    //Session timeout warning before 2 minute.
    var sessionTimeoutWarning = parseInt(sessionTimeout) - 2;

    //Session timeout in millisecond.
    var sTimeout = parseInt(sessionTimeout) * 60 * 1000;

    //setTimeout('SessionWarning()', sTimeout);

    setTimeout(' Redirect()', sTimeout);
    function SessionWarning() {
        //Calculating minutes before timeout in millisecond.
        var minutesForExpiry = (parseInt(sessionTimeout) - parseInt(sessionTimeoutWarning));

        var message = "Your session will expire in another " + minutesForExpiry + " mins! Please refresh the page before the session expires";
        alert(message);

        setTimeout('Redirect()', (minutesForExpiry * 1000 * 60));

    }

    function Redirect() {
        var msg = "Session expired. You will be redirected to login page";
        alert(msg);
        window.location = "LoginPage.aspx";
    }
    
</script>