HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>笔下光年</title>
</head>
<body>
<p>逐步改变 max-width, 从 "none" 到 "600px":<p>
<div id="myDIV">
<p>This DIV element does not have a pre-defined width.</p>
<p>Try resizing the browser window to see that width of this DIV element will grow/shrink along width the resizing, but it will never exceed 600 pixels in width.</p>
</div>
<p>max-width 属性支持动画效果。</p>
<p><b>注意:</b> 目前 max-height 属性在 Chrome 浏览器下不会改变 <em>gradually（灰阶）</em>, 在 Firefox 都无法起作用。</p>
<p><b>注意：</b>Internet Explorer 9 及更早 IE 版本不支持 CSS 动画。</p>
</body>
</html>
CSS
#myDIV {
background-color: lightblue;
overflow: auto;
border: 1px solid black;
-webkit-animation: mymove 5s infinite; /* Chrome, Safari, Opera */
animation: mymove 5s infinite;
}
/* Chrome, Safari, Opera */
@-webkit-keyframes mymove {
50% {max-width: 600px;}
}
/* Standard syntax */
@keyframes mymove {
50% {max-width: 600px;}
}