例如：
<body>
<div class="div1"></div>
</body>
CSS:
| @keyframes myfirst { (有的浏览器或者HTML版本过低就的加上-webkit-keyframes) | |
| 0% { | |
| width: 150px; | |
| } | |
| 30% { | |
| width: 300px; | |
| } | |
| 50% { | |
| width: 500px; | |
| } | |
| 100% { | |
| width: 600px; | |
| } | |
| } | |
| .div1 { | |
| width: 150px; | |
| height: 150px; | |
| background-color: #21bbca; | |
| /*-webkit-animation: myfirst 4s ease infinite;*/ | |
| } | |
原文：http://www.cnblogs.com/tk900123/p/4643889.html