今天要做的是一个轮播图，不过是属于全屏类型的轮播图，先来看看效果：
点击左右按钮能切换背景，达到轮播图效果
来看代码实现部分，首先是html:
<!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="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.14.0/css/all.min.css"
integrity="sha512-1PKOgIY59xJ8Co8+NE6FZ+LOAZKjy+KY8iq0G4B3CyeY6wYHN3yt9PW0XpSriVlkMXe40PTKnXrLnZ9+fkDaog=="
crossorigin="anonymous"
/>
<link rel="stylesheet" href="style.css" />
<title>Background Slider</title>
</head>
<body>
<div class="slider-container">
<div
class="slide active"
style="
background-image: url('https://images.unsplash.com/photo-1549880338-65ddcdfd017b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2100&q=80');
"
></div>
<div
class="slide"
style="
background-image: url('https://images.unsplash.com/photo-1511593358241-7eea1f3c84e5?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1934&q=80');
"
></div>
<div
class="slide"
style="
background-image: url('https://images.unsplash.com/photo-1495467033336-2effd8753d51?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2100&q=80');
"
></div>
<div
class="slide"
style="
background-image: url('https://images.unsplash.com/photo-1522735338363-cc7313be0ae0?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2689&q=80');
"
></div>
<div
class="slide"
style="
background-image: url('https://images.unsplash.com/photo-1559087867-ce4c91325525?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2100&q=80');
"
></div>
<!-- 左滑块按钮 -->
<button class="arrow left-arrow" id="left">
<i class="fas fa-arrow-left"></i>
</button>
<!-- 右滑块按钮 -->
<button class="arrow right-arrow" id="right">
<i class="fas fa-arrow-right"></i>
</button>
</div>
<script src="script.js"></script>
</body>
</html>
这里面没啥，就是几张图片，以及左右两个按钮的布局。
再来看css:
这里面的重点是蒙层，以及图片在默认的时候不显示，而在到它的时候就赋上active值让其显示。
* {
box-sizing: border-box;
}
body {
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
height: 100vh;
overflow: hidden;
margin: 0;
background-position: center center;
background-size: cover;
transition: 0.4s;
}
/* 添加一个蒙层 */
body::before {
content: '';
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100vh;
background-color: rgba(0, 0, 0, 0.7);
/* 防止覆盖住按钮 */
z-index: -1;
}
/* 小的滑框 */
.slider-container {
box-shadow: 0 3px 6px rgba(0, 0, 0, 0.16), 0 3px 6px rgba(0, 0, 0, 0.23);
height: 70vh;
width: 70vw;
position: relative;
/* 溢出内容隐藏 */
overflow: hidden;
}
/* 默认的时候背景图片 */
.slide {
opacity: 0;
height: 100vh;
width: 100vw;
background-position: center center;
background-size: cover;
position: absolute;
top: -15vh;
left: -15vw;
transition: 0.4s ease;
z-index: 1;
}
.slide.active {
opacity: 1;
}
/* 按钮 */
.arrow {
position: fixed;
background-color: transparent;
color: #fff;
padding: 20px;
font-size: 30px;
border: 2px solid orange;
top: 50%;
transform: translateY(-50%);
cursor: pointer;
}
/* 去掉轮廓 */
.arrow:focus {
outline: 0;
}
/* 左右按钮的位置 */
.left-arrow {
left: calc(15vw - 65px);
}
.right-arrow {
right: calc(15vw - 65px);
}
再来看JavaScript部分：
const body = document.body
const slides = document.querySelectorAll('.slide')
const leftBtn = document.getElementById('left')
const rightBtn = document.getElementById('right')
// 一开始默认下标为0，即显示第一张
let activeSlide = 0
// 左边的滑块，下标++，即下一张图片
rightBtn.addEventListener('click', () => {
activeSlide++
// 最后一张再往后就直接到第一张
if (activeSlide > slides.length - 1) {
activeSlide = 0
}
setBgToBody()
setActiveSlide()
})
// 右边的滑块，下标--，即上一张图片
leftBtn.addEventListener('click', () => {
activeSlide--
// 到第一张之后再上一张就到最后一张
if (activeSlide < 0) {
activeSlide = slides.length - 1
}
setBgToBody()
setActiveSlide()
})
setBgToBody()
// 改变背景图片
function setBgToBody() {
body.style.backgroundImage = slides[activeSlide].style.backgroundImage
}
// 到哪个图片的下标后就给它加上active，就能让图片opacity为1显示
/* 当前opacity为1显示之后其他的就为0了 */
function setActiveSlide() {
slides.forEach((slide) => slide.classList.remove('active'))
slides[activeSlide].classList.add('active')
}
注释写的比较清楚，大家如果有不懂的直接评论区问就行，这些分开来看还是很基础的。
今天的小demo就到这里了，大家加油！