<!DOCTYPE html>
<html>
<head>
<style>
div {position: absolute;}
#container div { background-color: lightblue;
border: 1px solid #333333;
width: 100px;
height: 100px;
opacity: 0.5;
}
div#myBox { opacity: 1;
background-color: coral;
z-index: 1;
animation: mymove 5s infinite linear;
}
@keyframes mymove { 50% {z-index: 5;}}
</style>
</head>
<body style="position:absolute">
<h1>z-index 的动画效果：</h1>
<p>逐渐将 "myBox" 的 z-index 属性从 1 改为 5，然后再改回 1：<p>
<div id="container">
<div id="myBox">myBox</div>
<div style="top:20px;left:20px;z-index:1;">z-index 1</div>
<div style="top:40px;left:40px;z-index:2;">z-index 2</div>
<div style="top:60px;left:60px;z-index:3;">z-index 3</div>
<div style="top:80px;left:80px;z-index:4;">z-index 4</div>
</div>
<p><b>注释：</b>CSS 动画在 Internet Explorer 9 以及更早版本中不起作用。</p>
</body>
</html>