简单的不用js就行
<!DOCTYPE HTML><html>
<head>
<meta charset= "utf8">
<title>untitled</title>
<link rel = "stylesheet" type = "text/css" href = "">
<style type = "text/css">
*{
margin: 0px
padding: 0px
}
#a{
position: absolute
width: 50px
height: 50px
background-color: #f3e9e0
border-radius: 50%
left: 400px
top: 200px
}
#a div{
position: absolute
width: 50px
height: 50px
border-radius: 50%
transition: all 0.5s
left: 0px
top: 0px
}
#a :nth-child(1){
background-color: #c1d4ed
}
#a :nth-child(2){
background-color: #7d6e69
}
#a :nth-child(3){
background-color: #dad6d5
}
#a :nth-child(4){
background-color: #caaa9d
}
#a :nth-child(5){
background-color: #6bdeff
}
#a:hover :nth-child(1){
left: 150px
top: -150px
}
#a:hover :nth-child(2){
left: 150px
top: 150px
}
#a:hover :nth-child(3){
left: 300px
top: -150px
}
#a:hover :nth-child(4){
left: 300px
top: 150px
}
#a:hover :nth-child(5){
left: 450px
top: 0px
}
</style>
</head>
<body>
<div id = 'a'>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</div>
</body>
</html>
鼠标伸到球上 自动扩散移动
1. js动画代码相对复杂一些2. 动画运行时，对动画的控制程度上，js能够让动画暂停、取消、终止，css动画不能添加事件
3.动画性能看，js动画多了一个js解析的过程，性能不如css动画好
引入jquery
然后给你要设置动画的对象增加或者删除css3动画的类就可以了。
如我这里用colorchange这个渐变类在css里面写好动画效果以后在js里面给对象添加上就可以实现动画了
<!DOCTYPE html><html>
<head lang="en">
<meta charset="UTF-8">
<title>Test</title>
<style type="text/css">
body{
padding: 20px
background-color:#FFF
}
.colorchange
{
animation:myfirst 5s
-moz-animation:myfirst 5s /* Firefox */
-webkit-animation:myfirst 5s /* Safari and Chrome */
-o-animation:myfirst 5s /* Opera */
}
@keyframes myfirst
{
from {background:red}
to {background:yellow}
}
@-moz-keyframes myfirst /* Firefox */
{
from {background:red}
to {background:yellow}
}
@-webkit-keyframes myfirst /* Safari and Chrome */
{
from {background:red}
to {background:yellow}
}
@-o-keyframes myfirst /* Opera */
{
from {background:red}
to {background:yellow}
}
#main{
width:100px
height:100px
background:red
}
#cgbt{
width: 100px
margin: 20px 0 0 0
text-align: center
cursor: pointer
}
#cgbt:hover{
background-color: #2D93CA
}
</style>
</head>
<body>
<div id="main">
我会变么？
</div>
<div id="cgbt">
点我让上面的变颜色
</div>
<script src="jquery-3.2.1.min.js" type="application/javascript"></script>
<script>
$(document).ready(function(){
$("#cgbt").click(function(){
$("#main").attr("class","colorchange")
})
})
</script>
</body>
</html>
