div水平垂直居中方式

div水平垂直居中方式
1
div{
width: 200px;
height: 200px;
background: green;
position:absolute;
left:0;
top: 0;
bottom: 0;
right: 0;
margin: auto;
}
2
div{
width:200px;
height: 200px;
background:green;
position: absolute;
left:50%;
top:50%;
margin-left:-100px;
margin-top:-100px;
}
3
div{
width: 200px;
height: 200px;
background: green;
position:absolute;
left:50%; /* 定位父级的50% /
top:50%;
transform: translate(-50%,-50%); /自己的50% */
}