php利用session进行登录验证

<?php

    require "../DB/MySQLHelper.php";
    require "../BLL/UserBLL.php";
    $result = -1;
    if(count($_POST)!=2)
    {
        echo $result;
        return;
    }
    $name = $_POST["name"];
    $password = $_POST["password"];

    $helper = new MySQLHelper();
    $helper->InitMySQL();
    $level = SelectUserLevel($helper,$name,$password);
    if($level != -1)
    {
        $result = $level;
        session_start();
        $_SESSION["user"] = true;
        $_SESSION["name"]=$name;
        $_SESSION["pwd"]=$password;
    }
    echo $result;
?>

<?php
    $user = false;
    session_start();
    //  判断是否登陆
    if (isset($_SESSION["user"]) && $_SESSION["user"] === true) {
        echo "true";
    } 
    else {
        $_SESSION["user"] = false;
        echo "false";
    }

?>