如图:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>上下左右居中</title>
<style>
html,body{
margin: 0; padding: 0;
}
.box {
background: red;
position:relative;
500px;
height: 500px;
top: 0;
left: 0;
margin: 0 auto;
}
.Center {
background-color: yellow; /*上下居中*/
position: absolute;
200px;
height: 200px;
top: 50%;
margin-top: -100px; /*height的一半
/*左右居中*/
left:0;
right: 0;
margin-left: auto;
margin-right: auto;
text-align: center;
line-height:200px;
}
</style>
</head>
<div class="box">
<div class="Center" >
我是要居中的元素
</div>
</div>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>上下左右居中</title>
<style type="text/css">
html,body{
margin: 0; padding: 0;
}
.box {
position: relative; /*这个可以去掉 看看效果哦，注意会有变化啊*/
600px; /*宽*/
height: 400px; /*高*/
background-color: rgba(212,66,33,.86);
margin: 0 auto;
}
.Absolute-Center {
160px;
height: 80px;
background-color: green;
position: absolute; top: 0; bottom: 0; left: 0; right: 0; /*css溢出法*/
margin: auto;
}
</style>
</head>
<body>
<div class="box">
<div class="Absolute-Center" >
我是要居中的元素
</div>
</div>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>上下左右居中</title>
<style type="text/css">
html,
body {
margin: 0;
padding: 0;
}
.box {
position: relative;
500px;
height: 500px;
background: red;
margin: 0 auto;
}
.Center {
200px;
height: 200px;
background-color: yellow;
position: relative;
top: 50%;
-moz-transform: translateY(-50%);
-webkit-transform: translateY(-50%);
-ms-transform: translateY(-50%);
-o-transform: translateY(-50%);
transform: translateY(-50%);
margin: auto;
text-align: center;
line-height: 200px;
}
</style>
</head>
<body>
<div class="box">
<div class="Center">
我是要居中的元素
</div>
</div>
</body>
</html>