css anim z-index - FACESOHO知行者

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8"> 
<title>小鸟启蒙(facesoho.com)</title> 
<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;
    -webkit-animation:mymove 5s infinite linear; /* Chrome, Safari, Opera */
    animation:mymove 5s infinite linear;
}

/* Chrome, Safari, Opera */
@-webkit-keyframes mymove {
    50% {z-index:5;}
}

/* Standard syntax */
@keyframes mymove {
    50% {z-index:5;}
}
</style>
</head>
<body style="position:absolute">

<p>z-index 属性支持动画效果。</p>
<p><b>注意：</b>Internet Explorer 9 及更早 IE 版本不支持 CSS 动画。</p>

<p>逐步改变 "myBox" 的 z-index 属性 从 1 到 5:<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>

</body>
</html>