PDO Prepared Statement允许执行javascript

我真的很困惑于PDO准备好的语句。我按照php.net文档中的说明做了所有事情。当我将JavaScript插入数据库，然后查询数据库并在页面上输出结果时，它会向我发出数据库上的JavaScript警报。

PDO是否保护用户数据免受这种类型的攻击，或者我们是否必须自己进行清理和转义，或者这里缺少什么。

<?php
    try {
        $db = new PDO('mysql:host=localhost;dbname=test', "root", "");
    } catch ( PDOException $e ) {
        print "Error!: " . $e->getMessage() . "<br/>";
        die();
    }
    $query = $db->query('SELECT * from users');
    if( $query->rowCount() ){
        $rows = $query->fetchAll( PDO::FETCH_OBJ);
        foreach( $rows as $row ){
            echo $row->user_name;
            echo "<br/>";
        }
    } else {
        echo "No results found";
    }
    $user_name = "<script type='"text/javascript'">alert('"Works'");</script>";
    $user_email = "example@gmail.com";
    $user_password = "password";
    $user_status = "1";
    $data = array(
        ":user_name" => $user_name,
        ":user_email" => $user_email,
        ":user_password" => $user_password,
        ":user_status" => $user_status
    );
    $sql = "INSERT INTO users (user_name, user_email, user_password, user_status) VALUES(:user_name, :user_email, :user_password, :user_status)";
    $prepare = $db->prepare($sql);
    $exec = $prepare->execute($data);
?>