方法一：
原理：在元素属性为table使用里使用vertical-align属性
<!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 media="screen">
#wrapper {
display: table;
height: 100px;
width: 60px;
}
#cell {
display: table-cell;
vertical-align: middle;
}
</style>
</head>
<body>
<div id="wrapper">
<div id="cell">
<div class="content">Content goes here</div>
</div>
</div>
</body>
</html>
方法二：
原理：对于有固定宽高的元素，利用绝对定位设置为：top: 0; bottom: 0; left: 0; right: 0; margin: auto因为这个元素有固定的高度，并不能距离上下都为0，margin： 0会使它居中显示。
<!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 media="screen">
#content {
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
margin: auto;
height: 140px;
width: 70%;
}
</style>
</head>
<body>
<div id="content">Content goes here</div>
</body>
</html>
方法三：
原理：利用行高，设置line-height和元素等高就行。
<!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 media="screen">
#content {
height: 100px;
line-height: 100px;
}
</style>
</head>
<body>
<div id="content">Content goes here</div>
</body>
</html>
方法四：
原理：使用css3的display: -webkit-box属性，再设置-webkit-box-pack: cente; -webkit-box-align:c enter
<!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 media="screen">
#content {
width:90px;
height:90px;
display:-webkit-box;
-webkit-box-pack:center;
-webkit-box-align:center;
}
</style>
</head>
<body>
<div id="content">Content Here</div>
</body>
</html>
方法五：
原理：使用css3的新属性transform: translate(x,y)属性
<!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 media="screen">
#content {
position: absolute;
width: 80px;
height: 80px;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
-webkit-transform: translate(-50%, -50%);
-moz-transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
background: green;
}
body {
position: relative;
height: 400px;
width: 400px;
}
</style>
</head>
<body>
<div id="content">Content Here</div>
</body>
</html>
方法六：
原理：使用:before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 media="screen">
#warp {
position: fixed;
display: block;
top: 0;
right: 0;
bottom: 0;
left: 0;
text-align: center;
background: rgba(0, 0, 0, .5);
}
#warp:before {
content: '';
display: inline-block;
vertical-align: middle;
height: 100%;
}
#warp #content {
display: inline-block;
width: 100px;
height: 100px;
line-height: 100px;
background: yellow;
}
</style>
</head>
<body>
<div id="warp">
<div id="content">Content Here</div>
</div>
</body>
</html>
