Posted in Javascript onOctober 30, 2020
要求：
- 鼠标经过轮播图模块，左右按钮显示，离开隐藏左右按钮
- 点击右侧按钮一次，图片往左播放一张，以此类推，左侧按钮同理
- 图片播放的同时，下面小圆圈模块跟随一起变化
- 点击小圆圈，可以播放相应图片
- 鼠标不经过轮播图，轮播图也会自动播放图片
- 鼠标经过，轮播图模块，自动播放停止
代码实现：
autoPlay.html（复制并保存为html文件，打开即可见效果）：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="https://blog-static.cnblogs.com/files/jacklzx/autoPlay.css" rel="external nofollow" >
<script src="https://blog-static.cnblogs.com/files/jacklzx/animate.js"></script>
<script src="https://blog-static.cnblogs.com/files/jacklzx/autoPlay.js"></script>
</head>
<body>
<div class="focus">
<!-- 左侧按钮 -->
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="arrow-l"><</a>
<!-- 右侧按钮 -->
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="arrow-r">></a>
<!-- 滚动区域 -->
<ul>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="https://s1.ax1x.com/2020/10/12/0W1wlt.jpg" alt=""></a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="https://s1.ax1x.com/2020/10/12/0W3nHS.jpg" alt=""></a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="https://s1.ax1x.com/2020/10/12/0Wtrmq.jpg" alt=""></a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="https://s1.ax1x.com/2020/10/12/0W1NYd.jpg" alt=""></a>
</li>
</ul>
<!-- 小圆圈 -->
<ol class="circle">
</ol>
</div>
</body>
</html>
autoPlay.css：
li {
list-style: none;
}
a {
text-decoration: none;
}
* {
margin: 0;
padding: 0;
}
body {
background-color: #00e1ff;
}
.focus {
overflow: hidden;
position: relative;
width: 721px;
height: 455px;
margin: 100px auto;
box-shadow: 10px 10px 20px rgba(0, 0, 0, 0.6);
border-radius: 40px;
}
.focus ul {
position: absolute;
top: 0;
left: 0;
width: 600%;
}
.focus ul li {
float: left;
}
.arrow-l {
display: none;
position: absolute;
top: 50%;
left: -12px;
margin-top: -20px;
width: 40px;
height: 40px;
background: rgba(0, 0, 0, .3);
text-align: center;
line-height: 40px;
color: #fff;
font-size: 18px;
border-radius: 0 50% 50% 0;
z-index: 999;
}
.arrow-r {
display: none;
position: absolute;
top: 50%;
right: -12px;
margin-top: -20px;
width: 40px;
height: 40px;
background: rgba(0, 0, 0, .3);
text-align: center;
line-height: 40px;
color: #fff;
font-size: 18px;
border-radius: 50% 0 0 50%;
z-index: 999;
}
.circle {
position: absolute;
bottom: 10px;
left: 50%;
transform: translateX(-50%);
}
.circle li {
float: left;
width: 12px;
height: 12px;
border: 2px solid rgba(255, 255, 255, .5);
margin: 0 4px;
border-radius: 50%;
cursor: pointer;
}
.current {
background-color: #fff;
box-shadow: 0 0 10px #fff;
}
autoPlay.js：
window.addEventListener('load', function() {
// 获取元素
var arrow_l = document.querySelector('.arrow-l');
var arrow_r = document.querySelector('.arrow-r');
var focus = document.querySelector('.focus');
var focusWidth = focus.offsetWidth;
// 自定义动画函数animate的参数，表示动画间隔
var step = 5;
// 鼠标经过focus 就显示左右按钮，停止计时器
focus.addEventListener('mouseenter', function() {
arrow_l.style.display = 'block';
arrow_r.style.display = 'block';
clearInterval(timer);
timer = null; // 清空计时器
});
// 鼠标离开focus 就隐藏左右按钮，调用定时器
focus.addEventListener('mouseleave', function() {
arrow_l.style.display = 'none';
arrow_r.style.display = 'none';
timer = setInterval(function() {
// 手动调用点击事件
arrow_r.click();
}, 2000);
});
var ul = focus.querySelector('ul');
var ol = focus.querySelector('.circle');
for (var i = 0; i < ul.children.length; i++) {
// 创建 li
var li = document.createElement('li');
// 设置自定义属性，记录小圆圈索引号
li.setAttribute('index', i);
// li插入ol
ol.appendChild(li);
// 小圈圈排他思想 生成圈圈同时 直接绑定事件
li.addEventListener('click', function() {
for (var i = 0; i < ol.children.length; i++) {
ol.children[i].className = '';
}
this.className = 'current';
// 点击小圈圈，移动图片，移动的是ul
// 点击li，拿到当前的索引号
var index = this.getAttribute('index');
// 当点击了li之后，就要把index给num，实现同步
num = index;
// 当点击了li之后，就要把index给circle，实现同步
circle = index;
animate(ul, -index * focusWidth, step);
});
}
// ol里第一个li的类名设置为current
ol.children[0].className = 'current';
var num = 0;
// circle控制小圆圈的播放
var circle = 0;
// 克隆第一章图片li，放到ul最后面
// 要在生成小圆圈之后克隆
var first = ul.children[0].cloneNode(true);
ul.appendChild(first);
// 点击右侧按钮，图片滚动
arrow_r.addEventListener('click', function() {
// 如果到了最后一张图片，ul要快速复原：left改为0
if (num == ul.children.length - 1) {
ul.style.left = 0;
num = 0;
}
num++;
animate(ul, -num * focusWidth, step);
// circle控制小圆圈的播放
circle++;
circle = circle == ol.children.length ? 0 : circle;
circleChange();
});
// 点击左侧按钮，图片滚动
arrow_l.addEventListener('click', function() {
if (num == 0) {
num = ul.children.length - 1;
ul.style.left = -num * focusWidth + 'px';
}
num--;
animate(ul, -num * focusWidth, step);
// circle控制小圆圈的播放
circle--;
circle = circle < 0 ? (ol.children.length - 1) : circle;
circleChange();
});
// 小圈圈改变样式
function circleChange() {
// 排他其他
for (var i = 0; i < ol.children.length; i++) {
ol.children[i].className = '';
}
// 留下自己
ol.children[circle].className = 'current';
}
// 自动播放功能
var timer = setInterval(function() {
// 手动调用点击事件
arrow_r.click();
}, 2000);
});
animate.js：
function animate(obj, target, time, callback) {
// 先清除以前的定时器，只保留当前的一个定时器执行
clearInterval(obj.timer);
obj.timer = setInterval(function() {
// 步长值写到定时器的里面，并设置为整数
var step = (target - obj.offsetLeft) / 10;
step = step > 0 ? Math.ceil(step) : Math.floor(step);
if (obj.offsetLeft == target) {
clearInterval(obj.timer);
// 回调函数写到定时器结束里面
callback && callback();
}
obj.style.left = obj.offsetLeft + step + 'px';
}, time);
}
以上就是JavaScript实现轮播图效果的详细内容，更多关于JavaScript 轮播图的资料请关注三水点靠木其它相关文章！
JavaScript实现轮播图效果
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