<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <h2></h2>

    <script>
        var person = {
            level: '2',
            name: '小丽',
            registTime: '2021-11-01',
        }
        var h2 = document.querySelector('h2');
        // 补全代码

        //现在日期
        var nd = new Date();
        // 目标日期
        var td = new Date(person.registTime);
        var diff = nd - td; //毫秒
        var day = parseInt(diff / (1000 * 60 * 60 * 24));

        h2.innerHTML = `尊贵的牛客网2级用户小丽您好，您已经注册牛客网${day}天啦~`;


    </script>
</body>

</html>