应用transition属性产生动画效果
css中的transition属性设置元素的变化过程所需的时间。
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
.adiv{
position:absolute;
text-align:center;
top:45%;
left:45%;
}
.bdiv{
border:2px solid black;
padding:25px 20px;
width:100px;
height:30px;
background-color:#33ffff;
color:white;
cursor:pointer;<!--设置鼠标手指状-->
}
.bdiv>span{
border:2px solid #33ffff;
position:absolute;
transition:0.8s;<!--设置变化所需要的时间-->
} .bdiv>span:nth-of-type(1){
top:0px;
left:-300px;
width:140px;
opacity:0;<!--设置透明，隐藏-->
}
.bdiv:hover>span:nth-of-type(1){
top:0px;
left:0px;
width:140px;
opacity:1;<!--设置不透明，显示-->
}
.bdiv>span:nth-of-type(2){
top:80px;
left:300px;
width:140px;
opacity:0;
}
.bdiv:hover>span:nth-of-type(2){
top:80px;
left:0px;
width:140px;
opacity:1;
}
.bdiv>span:nth-of-type(3){
top:160px;
left:0px;
height:80px;
opacity:0;
}
.bdiv:hover>span:nth-of-type(3){
top:0px;
left:0px;
height:80px;
opacity:1;
}
.bdiv>span:nth-of-type(4){
top:-160px;
left:140px;
height:80px;
opacity:0;
}
.bdiv:hover>span:nth-of-type(4){
top:0px;
left:140px;
height:80px;
opacity:1;
}
</style>
</head>
<body>
<div class="adiv">
<div class="bdiv">
鼠标放在这里
<span></span>
<span></span>
<span></span>
<span></span>
</div>
</div>
</body>
</html>
效果图（录制工具不好用，就不录光标了）
运用得好的话，效果是挺好看的。