js实现弹出框

实现效果：
代码：



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

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .x-tip-wrapper {
            position: relative;
            top: 100px;
            width: 500px;
            height: 300px;
            margin: 0 auto;
            color: #333;
            background-color: #dddddd;
        }

        .x-tip-top {
            width: 100%;
            height: 40px;
            background-color: rgb(67, 138, 254);
        }

        .x-tip-top-title {
            position: absolute;
            left: 50%;
            top: 7px;
            transform: translateX(-50%);
            display: inline-block;
            font-size: 20px;
            font-weight: 600;
            color: #fff;
        }

        .x-tip-top-back {
            position: absolute;
            top: 0px;
            right: 0px;
            width: 40px;
            height: 40px;
            font-size: 28px;
            color: #fff;
            text-align: center;
            line-height: 40px;
            cursor: pointer;
        }

        .x-tip-middle {
            display: flex;
            flex-direction: column;
            justify-content: space-around;
            width: 100%;
            height: 260px;
            text-align: center;
        }

        .x-tip-middle-tanhao {
            position: relative;
            width: 100%;
        }
        .x-tip-middle-tanhao-text {
            width: 30px;
            height: 30px;
            margin: 0 auto;
            background-color: red;
            font-size: 20px;
            font-weight: 700;
            text-align: center;
            line-height: 30px;
            color: #fff;
            border-radius: 50%;
        }
        .x-tip-middle-sub {
            position: relative;
            width: 100%;
        }
        .x-tip-middle-sub-text {
            width: 60px;
            height: 30px;
            margin: 0 auto;
            text-align: center;
            background-color: rgb(67, 138, 254);
            line-height: 30px;
            cursor: pointer;
            color: #fff;
        }
    </style>
</head>

<body>
    <div class="x-tip-wrapper" style="display: block;">
        <div class="x-tip-top">
            <div class="x-tip-top-title">提示</div>
            <div class="x-tip-top-back" onclick=aa()>X</div>
        </div>
        <div class="x-tip-middle">
            <div class="x-tip-middle-tanhao">
                <div class="x-tip-middle-tanhao-text">
                    !
                </div>
            </div>
            <div>
                对不起，你无法进行权限申请，
                <br>
                <br>
                请联系管理员！
            </div>
            <div class="x-tip-middle-sub">
                    <div class="x-tip-middle-sub-text" onclick=aa()>
                        确定
                    </div>
                </div>
        </div>
    </div>
    <script>
        var xDom = document.getElementsByClassName('x-tip-wrapper')[0]
    function aa () {
        xDom.style.display = 'none';
        console.log(111)
    }

    
    </script>
</body>

</html>