水平居中
行内元素居中
利用text-align 实现行内元素的居中1
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23<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent{
text-align: center;
}
.child{
display: inline-block;
}
</style>
</head>
<body>
<div class="parent">
<div class="child">Demo</div>
</div>
</body>
</html>
块级元素水平居中
可以使用外边距margin-left margin-right 设置为auto即可。则两边都可以水平空出距离。1
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23<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent{
margin: 0 auto;
width: 100px; /* 必须设置width */
}
</style>
</head>
<body>
<div class="parent">
Demo
</div>
</body>
</html>
使用table+margin方法。将子元素设置为块级表格来显示1
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25<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent{
display: table;
margin: 0 auto;
width:100px;
/* 必须设置width */
}
</style>
</head>
<body>
<div class="parent">
Demo
</div>
</body>
</html>
使用absolute+transform的方法。
将父元素设置为相对定位，再将子元素设置为绝对定位，向右移动子元素，移动距离为父元素的一半，
最后通过向左移动子元素的一半宽度来达到水平居中。
tranform属于css3的属性。1
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29<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent{
position: relative;
}
.child{
position: absolute;
left: 50%;
transform: translateX(-50%);
}
</style>
</head>
<body>
<div class="parent">
<div class="child">
Demo
</div>
</div>
</body>
</html>
使用flex+justify-content1
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10<style>
.parent {
display: flex;
justify-content:center;
}
</style>
浮动元素水平居中
1.对于定宽的浮动元素，通过子元素设置relative+负margin
2.对于不定宽的浮动元素，父子容器都用相对定位
3.通用方法(不管定宽还是不定宽)：都使用flex布局。
1.通过浮动1
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34<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.child {
position:relative;
left:50%;
margin-left:-250px;
}
</style>
</head>
<body>
<div class="parent">
<span class="child" style="float: left;width: 500px;">我是要居中的浮动元素</span>
</div>
</body>
</html>
不定宽居中1
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38<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent {
position:relative;
left:50%;
float: left;
}
p{
float: left;
position: relative;
right: 50%;
}
</style>
</head>
<body>
<div class="parent">
<p class="child">demo</p>
</div>
</body>
</html>
使用flex+justify-content来实现居中1
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33<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent {
display: flex;
justify-content: center;
}
.child{
width: 200px;
text-align: center;
float: left;
}
</style>
</head>
<body>
<div class="parent">
<p class="child">demo</p>
</div>
</body>
</html>
垂直居中
单行内联元素垂直居中
1 | <!DOCTYPE html> |
2.多行内联元素垂直居中
1.使用flex布局
利用flex布局实现垂直居中，其中flex-direction为column,column定义主轴方向为纵轴，1
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27<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
#box{
display: flex;
flex-direction: column;
justify-content: center;
height: 100px;
border: solid;
}
</style>
</head>
<body>
<div id = "box">
<span>单行内联元素</span>
</div>
</body>
</html>
利用表布局的属性1
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31<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="./css_center.css">
<style>
.parent{
display: table;
height: 100px;
border: solid;
}
.child{
display: table-cell;
vertical-align: middle;
}
</style>
</head>
<body>
<div class="parent">
<div class="child">
the more
</div>
</div>
</body>
</html>