本项目介绍一个展开图片的特效。
expanding-cards.png
HTML部分主要是5张图片，这里直接在html中添加了CSS样式，用来添加背景图片，其中每张图片还有一个标题。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link rel="stylesheet" href="style.css" />
<title>Expanding Cards</title>
</head>
<body>
<div class="container">
<div class="panel active" style="background: url('https://images.unsplash.com/photo-1558979158-65a1eaa08691?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1350&q=80')">
<h3>Explore The World</h3>
</div>
<div class="panel" style="background-image: url('https://images.unsplash.com/photo-1572276596237-5db2c3e16c5d?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1350&q=80')">
<h3>Wild Forest</h3>
</div>
<div class="panel" style="background-image: url('https://images.unsplash.com/photo-1507525428034-b723cf961d3e?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1353&q=80')">
<h3>Sunny Beach</h3>
</div>
<div class="panel" style="background-image: url('https://images.unsplash.com/photo-1551009175-8a68da93d5f9?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1351&q=80')">
<h3>City on Winter</h3>
</div>
<div class="panel" style="background-image: url('https://images.unsplash.com/photo-1549880338-65ddcdfd017b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1350&q=80')">
<h3>Mountains - Clouds</h3>
</div>
</div>
<script src="script.js"></script>
</body>
</html>
JS部分为每个图片添加点击监听事件，当点击图片时为图片所在的元素添加active类，并移除其它图片的active类。
const panels = document.querySelectorAll('.panel')
panels.forEach(panel => {
panel.addEventListener('click', () => {
removeActiveClasses()
panel.classList.add('active')
})
})
function removeActiveClasses() {
panels.forEach(panel => {
panel.classList.remove('active')
})
}
通过CSS部分我们可以发现，整个页面采用流式布局，普通图片占据0.5，active类所在图片占据5，这样就实现了点击查看当前图片，收缩其他图片。另外最后还做了设备兼容，针对宽度较小的设备隐藏最后两个图片。
* {
box-sizing: border-box;
}
body {
font-family: sans-serif;
display: flex;
align-items: center;
justify-content: center;
height: 100vh;
overflow: hidden;
margin: 0;
}
.container {
display: flex;
width: 90vw;
}
.panel {
background-size: cover;
background-position: center;
background-repeat: no-repeat;
height: 80vh;
border-radius: 50px;
color: #fff;
cursor: pointer;
flex: 0.5;
margin: 10px;
position: relative;
transition: all 700ms ease-in;
}
.panel h3 {
font-size: 24px;
position: absolute;
bottom: 20px;
left: 20px;
margin: 0;
opacity: 0;
}
.panel.active {
flex: 5;
}
.panel.active h3 {
opacity: 1;
transition: opacity 0.3s ease-in 0.4s;
}
@media (max-width: 480px) {
.container {
width: 100vw;
}
.panel:nth-of-type(4),
.panel:nth-of-type(5) {
display: none;
}
}
expanding-cards.gif
