css的旋转属性：
<!DOCTYPE html><html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
div{
background:black
width: 150px
height: 150px
}
div:hover{
transform:rotate(45deg)
/*旋转45度*/
transition:1s
/*过渡时间1s*/
}
</style>
</head>
<body>
<div></div>
</body>
</html>
<div class="change"></div>
<style>
.change {
animation: change 9s steps(1) infinite
background-repeat: no-repeat
background-position: center center
background-size: 100% auto
width: 200px
height: 100px
}
@keyframes change {
0% {
background-image: url(https://www.baidu.com/img/PCtm_d9c8750bed0b3c7d089fa7d55720d6cf.png)
}
33% {
background-image: url(https://www.duhongwei.site/img/201809/s1.png)
}
66% {
background-image: url(https://p4.ssl.qhimg.com/t01fcaa9d8a4d24b5f1.png)
}
}
</style>
纯 css 每3秒播一张图片。9s是总共时间，如果是4张图片这里写 12s
