直接上代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>居中</title>
<style>
{
margin: 0;
padding: 0;
}
/水平居中 margin : 0 auto; */
.box{
width: 300px;
height: 300px;
border: 2px solid red;
}
.img1{
display: block;
width: 100px;
height: 100px;
margin: 0 auto;
}
1.0.jpg
/*水平垂直居中*/
.box2{
width: 300px;
height: 300px;
position: relative;
border: 1px solid blue;
background: yellow;
}
.img2{
width: 100px;
height: 100px;
position: absolute;
top:50%;
left:50%;
margin-left: -50px;
margin-top: -50px;
}
2.0.jpg
/*水平垂直居中 2 */
.box3{
width: 300px;
height: 300px;
position: relative;
border: 1px solid blue;
}
.img3{
width: 100px;
height: 100px;
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
margin: auto;
}
3.0.jpg
/*水平垂直居中 3 css3新属性 */
.box4{
width: 300px;
height: 300px;
position: relative;
border: 1px solid blue;
}
.img4{
width: 100px;
height: 100px;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}
4.0.jpg
/* table-cell 将其变为表格 */
.box5{
width: 300px;
height: 300px;
display: table-cell;
vertical-align: middle;
text-align: center;
border: 1px solid blue;
}
.img5{
width: 100px;
height: 100px;
}
5.0.jpg
/* flex布局完成 */
.box6{
width: 300px;
height: 300px;
display: flex;
justify-content: center;
align-items: center;
border: 1px solid blue;
}
.img6{
width: 100px;
height: 100px;
}
6.0.jpg
</style>
</head>
<body>
<div class="box">
</div>
<div class="box2">
</div>
<div class="box3">
</div>
<div class="box4">
</div>
<div class="box5">
</div>
<div class="box6">
</div>
</body>
</html>
