JS——scroll动画

时间 2019-11-17

原文原文链接

固定导航栏html

一、计算导航栏到顶部的距离值浏览器

二、当scrollTop值大于这个距离值就添加定位，当小于距离值后解除定位动画

注意事项：当导航栏添加定位以后，导航栏就脱离了文档流，也就是不占位了，下面的盒子就会顶上来，因此要给下面盒子添加padding-top值this

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        body {
            height: 5000px;
        }

        .box1 {
            height: 40px;
            background-color: pink;
            overflow: hidden;
        }

        .box2 {
            height: 50px;
            background-color: yellow;
            font: 500 20px/50px "simsun";
            text-align: center;
        }

        .box3 {
            width: 820px;
            height: 512px;
            margin: 10px auto;
        }

        .fixed {
            position: fixed;
            width: 100%;
            top: 0;
            left: 0;
        }
    </style>
</head>
<body>
<div class="box1"></div>
<div class="box2">导航栏</div>
<div class="box3">
    <img src="images/nba.jpg">
</div>
<script>
    var banner = document.getElementsByTagName("div")[0];
    var nav = document.getElementsByTagName("div")[1];
    var lastDiv = document.getElementsByTagName("div")[2];
    window.onscroll = function () {
        if (scroll().top >= banner.offsetHeight) {
            nav.className = "box2 fixed";
            lastDiv.style.paddingTop = nav.offsetHeight + "px";
        } else {
            nav.className = "box2";
            lastDiv.style.paddingTop = "0px";
        }
    }

    function scroll() {
        return {
            "top": window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop,
            "left": window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft
        };
    }
</script>
</body>
</html>

两侧跟随广告spa

一、以前都是offsetLeft计算x轴上的移动，如今是计算y轴方向的移动code

二、鼠标滚动以后，遮盖的距离scrollTop值，须要和广告以前的定位Top值进行相加才是滚动的真正目标值htm

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        body {
            height: 5000px;
        }

        .box1 {
            width: 800px;
            margin: 50px auto;
            font: 500 25px/45px "simsun";
            color: red;
            text-align: center;
        }

        span {
            position: absolute;
            top: 300px;
            width: 40px;
            height: 120px;
            background: rgba(255, 142, 142, 0.3);
            font: 600 30px/60px "simsun";
            color: red;
            text-align: center;
        }

        .ad-left {
            left: 400px;
        }

        .ad-right {
            right: 400px;
        }
    </style>
</head>
<body>
<span class="ad-left">广<br>告</span>
<span class="ad-right">广<br>告</span>
<div class="box1">
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
</div>
<script>
    var sp1 = document.getElementsByTagName("span")[0];
    var sp2 = document.getElementsByTagName("span")[1];

    window.onscroll = function () {
        animate(sp1, scroll().top + 300);
        animate(sp2, scroll().top + 300);
    }

    function animate(ele, target) {
        clearInterval(ele.timer);
        ele.timer = setInterval(function () {
            var step = (target - ele.offsetTop) / 10;
            step = step > 0 ? Math.ceil(step) : Math.floor(step);
            ele.style.top = ele.offsetTop + step + "px";
            if (Math.abs(target - ele.offsetTop) <= Math.abs(step)) {
                ele.style.top = target + "px";
                clearInterval(ele.timer);
            }
        }, 15);
    }

    function scroll() {
        return {
            "top": window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop,
            "left": window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft
        };
    }
</script>
</body>
</html>

回到顶部blog

一、技术点：window.scrollTo(x,y)，以前都是移动某个元素，如今是须要移动整个显示区域，因此用window.scrollTo(x,y)ip

二、浏览器显示区域已经滚动的距离其实就是scrollTop值，作缓动画，只须要将这个值慢慢变小，一直到0便可。文档

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        body {
            height: 5000px;
        }

        .box1 {
            width: 800px;
            margin: 50px auto;
            font: 500 25px/45px "simsun";
            color: red;
            text-align: center;
        }

        span {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 40px;
            height: 120px;
            background: rgba(255, 142, 142, 0.3);
            font: 600 30px/30px "simsun";
            color: red;
            text-align: center;
            display: none;
        }

    </style>
</head>
<body>
<span>回<br>到<br>顶<br>部</span>
<div class="box1">
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
    锄禾日当午，汗滴禾下土，谁知盘中餐，粒粒皆幸苦<br>
</div>
<script>
    var sp = document.getElementsByTagName("span")[0];
    var target = 0;//目标位置
    var leader = 0;//显示区域自身的位置
    window.onscroll = function () {
        if (scroll().top > 400) {
            sp.style.display = "block";
        } else {
            sp.style.display = "none";
        }
        leader = scroll().top;
    }
    var timer = null;
    sp.onclick = function () {
        clearInterval(timer);
        timer = setInterval(function () {
            var step = (target - leader) / 10;
            step = step > 0 ? Math.ceil(step) : Math.floor(step);
            leader = leader + step;
            window.scrollTo(0, leader);
            if (Math.abs(target - leader) <= Math.abs(step)) {
                window.scrollTo(0, 0);
                clearInterval(timer);
            }

        }, 15);
    }

    function scroll() {
        return {
            "top": window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop,
            "left": window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft
        };
    }
</script>
</body>
</html>

楼层跨越

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            padding: 0;
            margin: 0;
            list-style: none;
        }

        body {
            height: 5000px;
        }

        ul {
            width: 800px;
            margin: 0 auto;
        }

        ul li {
            height: 400px;
        }

        ol {
            position: fixed;
            top: 150px;
            left: 350px;
        }

        ol li {
            width: 50px;
            height: 50px;
            font: 500 15px/50px "simsun";
            text-align: center;
            border: 1px solid #ccc;
            margin-top: -1px;
            cursor: pointer;
        }
    </style>
</head>
<body>
<ul>
    <li>上衣</li>
    <li>下衣</li>
    <li>春天</li>
    <li>夏衣</li>
    <li>秋衣</li>
    <li>冬衣</li>
</ul>
<ol>
    <li>上衣</li>
    <li>下衣</li>
    <li>春天</li>
    <li>夏衣</li>
    <li>秋衣</li>
    <li>冬衣</li>
</ol>
<script>
    var ul = document.getElementsByTagName("ul")[0];
    var uLiArr = ul.children;
    var ol = document.getElementsByTagName("ol")[0];
    var oLiArr = ol.children;
    var arrColor = ["pink", "blue", "yellow", "orange", "green", "red"];
    var timer = null;
    var dispalyArea = 0;//显示区域坐标
    var target = 0;//目标值
    for (var i = 0; i < arrColor.length; i++) {
        uLiArr[i].style.backgroundColor = arrColor[i];
        oLiArr[i].style.backgroundColor = arrColor[i];
        oLiArr[i].index = uLiArr[i].offsetTop;
        //显示区域的scrollTop值与目标的scrollTop值差值
        oLiArr[i].onclick = function () {
            target = this.index;
            clearInterval(timer);
            timer = setInterval(function () {
                var step = (target - dispalyArea) / 10;
                step = step > 0 ? Math.ceil(step) : Math.floor(step);
                dispalyArea = dispalyArea + step;
                window.scrollTo(0, dispalyArea);
                if (Math.abs(target - dispalyArea) <= Math.abs(step)) {
                    clearInterval(timer);
                    window.scrollTo(0, target);
                }
            }, 15);
        }
    }
    window.onscroll = function () {
        dispalyArea = scroll().top;
    }

    function scroll() {
        return {
            "top": window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop,
            "left": window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft
        };
    }
</script>
</body>
</html>