在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(cainiaoplay.com)</title>
<style>div
{
	width:100px;
	height:100px;
	background:red;
	position:relative;
	animation:myfirst 5s infinite;
	animation-direction:alternate;

	/* Safari 和 Chrome */
	-webkit-animation:myfirst 5s infinite;
	-webkit-animation-direction:alternate;
}

@keyframes myfirst
{
	0%   {background:red; left:0px; top:0px;}
	25%  {background:yellow; left:200px; top:0px;}
	50%  {background:blue; left:200px; top:200px;}
	75%  {background:green; left:0px; top:200px;}
	100% {background:red; left:0px; top:0px;}
}

@-webkit-keyframes myfirst /* Safari 和 Chrome */
{
	0%   {background:red; left:0px; top:0px;}
	25%  {background:yellow; left:200px; top:0px;}
	50%  {background:blue; left:200px; top:200px;}
	75%  {background:green; left:0px; top:200px;}
	100% {background:red; left:0px; top:0px;}
}
</style>
</head>
<body>

<p><strong>注意：</strong>Internet Explorer 9 及其之前的版本不支持 animation-direction 属性。</p>

<div></div>

</body>
</html>
源代码

动行结果
