仿京东头部固定导航栏(滑动滑轮顶部固定)

最新推荐文章于 2024-07-15 23:16:45 发布

cashAAone

最新推荐文章于 2024-07-15 23:16:45 发布

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文章标签：前端 javascript css html css3

本文链接：https://blog.youkuaiyun.com/cashAAone/article/details/125982545

版权

<!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>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        html {
            scroll-behavior: smooth;
        }
        
        .content {
            overflow: hidden;
            width: 1000px;
            height: 3000px;
            background-color: pink;
            margin: 0 auto;
        }
        
        .backtop {
            display: none;
            width: 50px;
            left: 50%;
            margin: 0 0 0 505px;
            position: fixed;
            bottom: 60px;
            z-index: 100;
        }
        
        .backtop a {
            height: 50px;
            width: 50px;
            background: url(./images/bg2.png) 0 -600px no-repeat;
            opacity: 0.35;
            overflow: hidden;
            display: block;
            text-indent: -999em;
            cursor: pointer;
        }
        
        .header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 80px;
            background-color: purple;
            text-align: center;
            color: #fff;
            line-height: 80px;
            font-size: 30px;
            transition: all .3s;
            opacity: 1;
        }
        
        .sk {
            width: 300px;
            height: 300px;
            background-color: skyblue;
            margin-top: 500px;
        }
    </style>
</head>

<body>
    <div class="header">我是顶部导航栏</div>
    <div class="content">
        <div class="sk">秒杀模块</div>
    </div>
    <div class="backtop">
        <img src="./images/close2.png" alt="">
        <a href="javascript:;"></a>
    </div>
    <script>
        //获取事件源  顶部和秒杀
        const header = document.querySelector('.header')
        const sk = document.querySelector('.sk')
        console.log(sk.offsetTop)
            //注册事件  滑轮
        window.addEventListener('scroll', function() {
            //要获取当前页面的滚动条纵坐标位置，用：document.documentElement.scrollTop;
            const n = document.documentElement.scrollTop
                // 判断n >= sk.offsetTop(sk.offsetTop其实就是距顶部500px)
                //然后用opacity是否隐藏或显示
            header.style.opacity = n >= sk.offsetTop ? 1 : 0
        })
    </script>
</body>

</html>