PHPsession丢失有关问题

open();
    $user     = trim($_POST["user"]);
    $password = trim($_POST["password"]);
    $yz       = trim($_POST["yz"]);    
    //echo $yz;
    if($yz == $_SESSION['checkcode'])
    {
        $sql = "select * from admin where adname= '$user' and adpassword = '$password'";    
        $m->get($sql);
        if($m->getRows()){
            $n = $m->getValue(0,'adname');
            $j = $m->getValue(0,'adjurisdiction');
            $add = $m->getValue(0,'aduid');
            $_SESSION["admin"] = $n; 
            $_SESSION["jur"] = $j;
            $_SESSION["aduid"] = $add;
            $sid = session_id();
            //echo $sid;
            //echo $_SESSION["admin"];
               header( "Location: ../member/index.php?sid={$sid}"); 
            //$url = "./member/index.php";
            //header("location:./member/index.php");
            
    
        }else{
            echo "";
        }    
    
    }else{
        echo "";
    }
?>