CSS3/CSS之居中解析(水平+垂直居中、水平居中,垂直居中)
首先,我们来看下垂直居中:
(1)、如果是单行文本,则可以设置的line-height的数值,让其等于父级元素的高度!
<!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>document</title> <style> .box{ background: green; height:200px; } a {height:100%; line-height: 200px; color:red; } </style> </head> <body> <div class="box"> <a href="">ggg </a> </div> </body> </html>
(2)、如果元素是行内块级元素,一般会使用diaplay:inline-block,vertical-align:middle,还有一个伪元素让元素内容处于容器*!给父元素添加伪元素!
<!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>document</title> <style> .box { background: green; height:200px; } .box::after, .box2{ display:inline-block; vertical-align: middle; } .box::after{ content:''; height:100%; } .box2{background-color:red;width:20px;height:20px;} </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
(3)、通过display:flex来实现垂直居中;
父级:display:flex;
子元素:align-self:center;
<!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>document</title> <style> .box { background: green; height:300px; width: 600px; display:flex; } .box2{background:red; width:30%; height:30%; align-self: center; } </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
(4)、使用display:table进行垂直居中!
给父元素设置display:table;子元素设置为display:table-cell;
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; display:table; } .box .box2{ color:red; display:table-cell; vertical-align: middle; } </style> </head> <body> <div class="box"> <div class="box2">ddddd</div> </div> </body> </html>
(5),已经知道父元素的高度,给子元素相对定位,在通过translay()得到垂直居中
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; } .box .box2{ background-color:red; width:50%; height:50%; position: relative; top:50%; transform:translatey(-50%); } </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
6)、父元素高度不知道,同过transform实现,先给父元素相对定位,在给子元素绝对定位
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; position: relative; } .box .box2{ background-color:red; width:50%; height:50%; position: absolute; top:50%; transform:translatey(-50%); } </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
二、水平居中:
(1)、行内元素方案,只要把行内元素包裹 在一个盒子中,并且在他父级元素添加如下属性:text-align:center;
<!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>document</title>
<style>
.box {
background-color: green;
height:300px;
width: 600px;
text-align:center;
}
p{color:red;}
</style>
</head>
<body>
<div class="box">
<p>1111</p>
</div>
</body>
</html>
(2)、单个块状元素解决方案:
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; text-align:center; } .box2{ background-color: red; width: 20px; height: 20px; margin:0 auto; } </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
3)、多个块状元素解决方案:父元素设置为text-align:center;子元素设置为:display:inline-block;
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!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; text-align:center; } .box2, .box3{ background-color: red; width: 20px; height: 20px; display:inline-block; } </style> </head> <body> <div class="box"> <div class="box2"></div> <div class="box3"></div> </div> </body> </html>
也可以使用flexbox来实现:
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; display:flex; justify-content:center; } .box2, .box3, .box4{ background-color: red; width: 20px; height: 20px; } </style> </head> <body> <div class="box"> <div class="box2"></div> <div class="box3"></div> <div class="box4"></div> </div> </body> </html>
(4)、不定宽度块元素水平居中:
<!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>document</title> <style> .box { float:left; position: relative; left:50%; } .box ul{ position:relative; left:-50%; } </style> </head> <body> <div class="box"> <ul> <li>1111</li> <li>111</li> <li>111</li> </ul> </div> </body> </html>
三:实现水平+垂直居中,也就是在*:(1)单行行内元素:父元素设置:text-align:center,display:table-cell;vertical-align:middle,在这里,图片,文字,都是一样的操作
<!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>document</title> <style> .box { background-color: #ccc; width:500px; height: 500px; display:table-cell; text-align: center; vertical-align: middle; } img{width:50px; height: 50px;} </style> </head> <body> <div class="box"> <img src="5.jpg" alt=""> </div> </body> </html>
文字在*,还可以父级设置为text-align:center;line-height设置为父元素的height
<!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>document</title> <style> .box { background-color: #ccc; width:500px; height: 500px; text-align: center; } p{line-height: 500px;} </style> </head> <body> <div class="box"> <p>1111</p> </div> </body>
(2)对于单个块级元素,父元素设置为相对定位,子元素设置为绝对定位高度,宽度为50%
!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>document</title> <style> .box { background-color: #ccc; width:500px; height: 500px; position: relative; } .box2{position: absolute; top:50%; left:50%; background-color: black; width: 20px; height: 20px;} </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
(3)、flex实现不定宽度水平+垂直居中
<!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>document</title> <style> .box { background-color: green; height:300px; width: 600px; display:flex; justify-content:center; align-items:center; } .box2, .box3, .box4{ background-color: red; width: 20px; height: 20px; } </style> </head> <body> <div class="box"> <div class="box2"></div> </div> </body> </html>
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原文链接:
<!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>document</title> <style> .box{ background: green; height:200px; } a {height:100%; line-height: 200px; color:red;} </style></head><body> <div class="box"> <a href="">ggg </a> </div></body></html>————————————————版权声明:本文为csdn博主「左手写爱等等」的原创文章,遵循 cc 4.0 by-sa 版权协议,转载请附上原文出处链接及本声明。原文链接:https://blog.csdn.net/qq_35788269/article/details/80691114
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