这篇文章主要介绍“如何用JavaScript实现轮播图效果”，在日常操作中，相信很多人在如何用JavaScript实现轮播图效果问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”如何用JavaScript实现轮播图效果”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
实现代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
* {
margin: 0;
padding: 0;
}
ul {
list-style: none;
}
#box {
margin: 30px auto;
width: 590px;
height: 340px;
position: relative;
}
#banner-list > li {
position: absolute;
left: 0;
right: 0;
opacity: 0;
/*过渡动画*/
transition: opacity 2s ease;
}
#left, #right {
width: 30px;
height: 60px;
text-align: center;
line-height: 60px;
font-size: 24px;
color: rgba(255,255,255,0.7);
background-color: rgba(0,0,0,0.3);
position: absolute;
top: 50%;
margin-top: -30px;
z-index: 3;
}
#right {
right: 0;
}
#tag-list {
width: 130px;
position: absolute;
left: 50%;
bottom: 8px;
margin-left: -55px;
}
#tag-list > li {
float: left;
width: 18px;
height: 18px;
margin: 4px;
text-align: center;
line-height: 18px;
font-size: 13px;
background-color: white;
border-radius: 9px;
/*过渡动画*/
transition: background-color 1s ease;
}
</style>
<script>
window.onload = function (){
//获取tag_list和圆圈list
var tag_list = document.getElementById("tag-list");
var list = tag_list.children;
//1.获取 ul(banner_list) 和 所有的li
let banner_list = document.getElementById("banner-list");
let bannerLi = banner_list.children;
//2.默认显示第一张banner
bannerLi[0].className = "current-banner"
bannerLi[0].style.opacity = 1
list[0].style.backgroundColor = "red"
//3.索引从0开始，默认显示第一张。
//count表示当前显示页面的索引
let count = 0;
//4.点击>向右切换
var right = document.getElementById("right");
right.onclick = function (){
//4.1先将当前页面隐藏
bannerLi[count].className = ""
bannerLi[count].style.opacity = 0
list[count].style.backgroundColor = "white"
//4.2.页码加1,当到第6张(index=5)，切换到第一张(index=0)
if (++count == 5){
count = 0
}
//4.3 设置当前页码为显示
bannerLi[count].className = "current-banner"
bannerLi[count].style.opacity = 1
list[count].style.backgroundColor = "red"
}
//和right差不多，修改下条件
var left = document.getElementById("left");
left.onclick = function (){
//4.1先将当前页面隐藏
bannerLi[count].className = ""
bannerLi[count].style.opacity = 0
list[count].style.backgroundColor = "white"
//4.2.页码减1,当到第0张(index=-1)，切换到第5张(index=4)
if (--count == -1){
count = 4
}
//4.3 设置当前页码为显示
bannerLi[count].className = "current-banner"
bannerLi[count].style.opacity = 1
list[count].style.backgroundColor = "red"
}
//给所有圆圈绑定鼠标事件
for (let i = 0; i < list.length; i++) {
list[i].onmouseenter= function (){
//设置圆圈样式
list[count].style.backgroundColor = "white"
list[i].style.backgroundColor = "red"
//设置banner图样式
bannerLi[count].className = ""
bannerLi[count].style.opacity = 0
bannerLi[i].className = "current-banner"
bannerLi[i].style.opacity = 1
//将count置为i
count = i
}
}
}
</script>
</head>
<body>
<div id="box">
<ul id="banner-list">
<li class="current-banner"><img src="banner-img/11.jpg" alt=""></li>
<li><img src="banner-img/22.jpg" alt=""></li>
<li><img src="banner-img/33.jpg" alt=""></li>
<li><img src="banner-img/44.jpg" alt=""></li>
<li><img src="banner-img/55.jpg" alt=""></li>
</ul>
<span id="left"><</span>
<span id="right">></span>
<div>
<ul id="tag-list">
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
</ul>
</div>
</div>
</body>
</html>到此，关于“如何用JavaScript实现轮播图效果”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注亿速云网站，小编会继续努力为大家带来更多实用的文章！
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