1.最普通型(水平居中)
div{200px;margin: 0 auto;}
2.运用绝对定位来居中
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style type="text/css">
.con{
position: absolute;
300px;
height: 200px;
left: 0;
right: 0;
top: 0;
bottom: 0;
background-color: red;
margin: auto;
}
</style>
</head>
<body>
<div class="con"></div>
</body>
</html>
3.运用left和top的百分比来设定
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style type="text/css">
.con{
position: absolute;
300px;
height: 200px;
left: 50%;
top: 50%;
margin-left: -150px;
margin-top: -100px;
background-color: red;
}
</style>
</head>
<body>
<div class="con"></div>
</body>
</html>
4.transform()
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style type="text/css">
.con{
position: absolute;
300px;
height: 200px;
left: 50%;
top: 50%;
transform: translate(-50%,-50%);
background-color: red;
}
</style>
</head>
<body>
<div class="con"></div>
</body>
</html>