代码：
<!DOCTYPE html>
<html lang="ch">
<head>
<meta charset="UTF-8">
<title>点击按钮实现多张图片的循环切换</title>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
.img-wrapper {
width: 520px;
height: 520px;
background-size: contain;
overflow: hidden;
margin: 50px auto;
background-color: green;
}
.img-wrapper img{
width: 533px;
height: 300px;
}
.img-wrapper p {
text-align: center;
height: 20px;
line-height: 20px;
font-size: 16px;
margin-bottom: 10px;
margin-top: 8px;
}
.img-wrapper button {
margin: 12px 93px;
font-size: 18px;
}
</style>
<script type="text/javascript">
window.onload = function () {
let prev = document.getElementById("prev");
let next = document.getElementById("next");
let img = document.getElementsByTagName("img")[0];
let info = document.getElementById("info");
//创建一个数组存储照片的路径
let imgArr = ["img/111.jpg", "img/222.jpg", "img/333.jpg", "img/444.jpg", "img/555.jpg", "img/666.jpg"];
let index = 0;
info.innerText = "一共有" + imgArr.length + "张照片，现在是第" + (index + 1) + "张";
prev.onclick = function () {
index--;
prev.style.backgroundColor="#ff4c31";
if (index < 0) {
index = imgArr.length - 1;
}
img.src = imgArr[index];
info.innerText = "一共有" + imgArr.length + "张照片，现在是第" + (index + 1) + "张";
};
next.onclick = function () {
index++;
next.style.backgroundColor="#ff4c31";
if (index > imgArr.length - 1) {
index = 0;
}
img.src = imgArr[index];
info.innerText = "一共有" + imgArr.length + "张照片，现在是第" + (index + 1) + "张";
};
};
</script>
</head>
<body>
<div class="img-wrapper">
<p id="info"></p>
<img src="img/111.jpg">
<button id="prev">上一张</button>
<button id="next">下一张</button>
</div>
</body>
</html>
效果：
