css在盒子中垂直居中和固定居中

顶部固定居中

 <div class="w960 fixed">我是固定的</div>.w960{
width: 960px;
margin:0 auto;
}
.fixed{
position: absolute;
top:0;
left: 0;
right: 0;
height: 90px;
background: #ececec;
}

垂直居中

<div id="box"><div class="son">ssss</div></div>#box {width: 600px;height: 500px;position: relative;border: 1px solid #f00;
}
.son {width: 100px;height: 100px;border: 1px solid #ecc;position: absolute;left: 50%;margin-left: -50px;top: 50%;margin-top: -50px;
}