CSS实现垂直居中

html的内容：

<div class="box box1">
        <span>垂直居中</span>
</div>

css的内容
1..box1{
display: table-cell;
vertical-align: middle;
text-align: center;
}
.2.box2{
display: flex;
justify-content:center;
align-items:Center;
}
3
box3{position:relative;}
.box3 span{
position: absolute;
width:100px;
height: 50px;
top:50%;
left:50%;
margin-left:-50px;
margin-top:-25px;
text-align: center;
}
4
.box4 span{
width: 50%;
height: 50%;
background: #000;
overflow: auto;
margin: auto;
position: absolute;
top: 0; left: 0; bottom: 0; right: 0;
}
5
.box6 span{
position: absolute;
top:50%;
left:50%;
width:100%;
transform:translate(-50%,-50%);
text-align: center;
}
6
.box7{
text-align:center;
font-size:0;
}
.box7 span{
vertical-align:middle;
display:inline-block;
font-size:16px;
}
.box7:after{
content:”;
width:0;
height:100%;
display:inline-block;
vertical-align:middle;
}
7
.box8{
display: flex;
text-align: center;
}
.box8 span{margin: auto;}
8
.box9{
display: -webkit-box;
-webkit-box-pack:center;
-webkit-box-align:center;
-webkit-box-orient: vertical;
text-align: center
}
9
html

<div class="floater"></div>  
<div class="content"> Content here </div>  

css

.floater {
float:left;
height:50%;
margin-bottom:-120px;
}
.content {
clear:both;
height:240px;
position:relative;
}