效果预览按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。https://codepen.io/comehope/pen/gBKWdW可交互视频此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。请用 chrome, safari, edge 打开观看。第 1 部分：https://scrimba.com/p/pEgDAM/cazRgcL第 2 部分：https://scrimba.com/p/pEgDAM/ceDK7cB源代码下载每日前端实战系列的全部源代码请从 github 下载：https://github.com/comehope/front-end-daily-challenges代码解读定义 dom，包含 5 个子元素，分别代表 iphone, mini, ipad, macbook, imac 这 5 种设备：<div class=“container”> <div class=“device iphone”></div> <div class=“device mini”></div> <div class=“device ipad”></div> <div class=“device macbook”></div> <div class=“device imac”></div></div>居中显示：body { margin: 0; height: 100vh; display: flex; align-items: center; justify-content: center; background-color: #aaa;}设置容器中子元素的布局方式：.container { position: relative; display: flex; flex-direction: column; align-items: center;}设置设备的共有属性，线性渐变图案将作为屏幕的背景：.device { box-sizing: border-box; position: relative; display: flex; justify-content: center; background: linear-gradient(120deg, #ddd 30%, #ccc 30%);}.device::before,.device::after { content: ‘’; position: absolute;}iphone, mini, ipad 的造型相似，都有顶部摄像头、传感器开口和底部按钮，所以这些共有属性可以一起设置，用 ::before 伪元素画出顶部细节，::after 伪元素画出底部按钮：.iphone::before,.mini::before,.ipad::before { width: 2px; height: 2px; border-style: solid; border-color: #a5adbe; border-width: 0 12px 0 2px;}.iphone::after,.mini::after,.ipad::after { width: 8px; height: 8px; background-color: white; border-radius: 50%;}接下来逐个画出设备。先画出 iphone 的轮廓：.iphone { width: 59px; height: 124px; border: #484f5e solid; border-width: 18px 4px; border-radius: 6px;}定位 iphone 的顶部和底部细节：.iphone::before { top: -10px;}.iphone::after { bottom: -13px;}类似地，画出 mini：.mini { width: 93px; height: 138px; border: #484f5e solid; border-width: 14px 5px; border-radius: 10px;}.mini::before { top: -8px;}.mini::after { bottom: -11px;}再画出 ipad：.ipad { width: 134px; height: 176px; border: #484f5e solid; border-width: 18px 13px; border-radius: 12px;}.ipad::before { top: -10px;}.ipad::after { bottom: -13px;}接下来画 macbook，先画屏幕：.macbook { width: 234px; height: 155px; border: 8px solid #484f5e; border-radius: 7px 7px 0 0;}用 ::before 伪元素画出摄像头：.macbook::before { width: 294px; height: 14px; background-color: #e8ebf0; top: calc(100% + 8px); border-radius: 0 0 14px 14px;}用 ::after 伪元素画出主机：.macbook::after { width: 3px; height: 3px; background-color: #a5adbe; top: -6px; border-radius: 50%;}接下来画 imac，先画屏幕，屏幕的左、上、右的黑色边框没有用 border 属性画，是因为 border 会在端点处遗留一个斜角，所以改用 box-shadow 实现：.imac { width: 360px; height: 215px; border-radius: 10px; box-shadow: inset 0 14px #484f5e, inset 14px 0 #484f5e, inset -14px 0 #484f5e; border-bottom: 33px solid #e8ebf1; transform: translateY(14px);}用 ::before 伪元素画出梯形的底座：.imac::before { width: 90px; height: 0; top: calc(100% + 33px); border: solid transparent; border-bottom-color: #e2e4e8; border-width: 0 10px 47px 10px;}用 ::after 伪元素画出顶部的摄像头和屏幕底部的按钮，注意按钮是用 box-shadow 实现的：.imac::after { width: 4px; height: 4px; background-color: #a5adbe; top: 5px; border-radius: 50%; box-shadow: 0 191px 0 4px #464e5d;}至此，设备全部绘制完成。删除除 iphone 之外的其他设备的 dom 元素，只保留 1 个 dom 元素，后面的动画效果都在这个 dom 元素上变化：<div class=“container”> <div class=“device iphone”></div> <!– <div class=“device mini”></div> <div class=“device ipad”></div> <div class=“device macbook”></div> <div class=“device imac”></div> –> </div>设置容器尺寸，子元素垂直居中，设备的高度占容器高度的 75%：.container { width: 360px; height: 350px; justify-content: center;}.device { transform: translateY(-25%);}在 dom 中增加 2 个按钮元素，分别用 .left 和 .right 表示：<div class=“container”> <div class=“device iphone”></div> <div class=“buttons”> <span class=“left”></span> <span class=“right”></span> </div></div>定位按钮的位置：.buttons { position: absolute; width: inherit; font-size: 30px; height: 2em; bottom: 0; display: flex; justify-content: space-around;}.buttons > * { position: relative; width: 4em;}按钮为向左和向右的箭头：.buttons > *::before { position: absolute;}.buttons .left::before { content: ‘←’; right: 0;}.buttons .right::before { content: ‘→’;}设置按钮样式为圆形：.buttons > *t::before { position: absolute; width: 2em; height: 2em; background-color: #484f5e; color: silver; text-align: center; line-height: 2em; border-radius: 1em; cursor: pointer;}增加鼠标悬停效果：.buttons > *::before { transition: 0.2s;}.buttons .left:hover::before { width: 4em; content: ‘⟵’;}.buttons .right:hover::before { width: 4em; content: ‘⟶’;}增加按钮点击效果：.buttons > *:active { transform: scale(0.9); filter: brightness(0.8);}至此，按钮制作完毕，接下来创建交互脚本。定义一个获取元素的函数 $：const $ = (className) => document.getElementsByClassName(className)[0]定义一个存放设备名称的数组：let devices = [‘iphone’, ‘mini’, ‘ipad’, ‘macbook’, ‘imac’]定义点击行为对数据的加工方法，当点击左侧按钮时，把数组最左边的 1 个元素移到最右边，相反地，当点击右侧按钮时，把数组最右边的 1 个元素移到最左边，这样就可以从 2 个方向循环遍历数组了：let loop = { ’left’: () => devices.unshift(devices.pop()), ‘right’: () => devices.push(devices.shift())}定义点击事件，根据数组的变化切换设备：Array.from($(‘buttons’).children).forEach(element => element.addEventListener(‘click’, function(e) { loope.target.className $(‘device’).className = ‘device ’ + devices[0] }))最后，设置设备切换的缓动效果：.device,.device::before,.device::after { transition: 0.4s cubic-bezier(0.5, 1.7, 0.5, 1.2);}大功告成！