手写垂直水平居中
常见的垂直水平居中方法
- position+margin负值的方法（固定宽高）
- position+margin:auto （固定宽高)
- display:table-cell + vertical-align:middle （固定宽度）
- position+transform（不需要固定宽高）
- flex （不需要固定宽高）
代码
position+margin负值的方法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>垂直水平居中</title>
</head>
<style>
* {
margin: 0;
padding: 0;
}
.box {
position: relative;
width: 500px;
height: 500px;
border: 5px solid red;
}
.item {
position: absolute;
left: 50%;
top: 50%;
margin-top: -150px;
margin-left: -100px;
width: 200px;
height: 300px;
background-color: #ccc;
}
</style>
<body>
<div class="box">
<div class="item">垂直水平</div>
</div>
</body>
</html>
position+margin:auto
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>垂直水平居中</title>
</head>
<style>
*{
margin: 0;
padding: 0;
}
.box{
position: relative;
width: 500px;
height: 500px;
border: 5px solid red;
}
.item{
position: absolute;
left: 0;
top: 0;
right: 0;
bottom: 0;
margin: auto;
width: 200px;
height: 300px;
background-color: #ccc;
}
</style>
<body>
<div class="box">
<div class="item">垂直水平居中</div>
</div>
</body>
</html>
display:table-cell + vertical-align:middle
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>垂直水平居中</title>
</head>
<style>
* {
margin: 0;
padding: 0;
}
.box {
display: table-cell;
vertical-align: middle;
width: 500px;
height: 500px;
border: 5px solid red;
}
.item {
margin: auto;
width: 200px;
height: 300px;
background-color: #ccc;
}
</style>
<body>
<div class="box">
<div class="item">垂直水平居中</div>
</div>
</body>
</html>
position+transform
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>垂直水平居中</title>
</head>
<style>
* {
margin: 0;
padding: 0;
}
.box {
position: relative;
width: 500px;
height: 500px;
border: 5px solid red;
}
.item {
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%,-50%);
background-color: #ccc;
}
</style>
<body>
<div class="box">
<div class="item">垂直水平居中</div>
</div>
</body>
</html>
flex
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>垂直水平居中</title>
</head>
<style>
* {
margin: 0;
padding: 0;
}
.box {
display: flex;
justify-content: center;
align-items: center;
width: 500px;
height: 500px;
border: 5px solid red;
}
.item {
background-color: #ccc;
}
</style>
<body>
<div class="box">
<div class="item">垂直水平居中</div>
</div>
</body>
</html>
