图片水平垂直居中
代码如下：
<!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>Demo</title>
</head>
<style>
#content {
margin:0 auto;
border:1px red solid;
text-align:center;
width:500px;
height:300px;
}
#content::before {
content: '';
display: inline-block;
height:100%;
vertical-align: middle;
}
#content img {
vertical-align:middle;
}
</style>
<body>
<div id = "content">
<img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRD0irY_XEioTD1eBezJCKi3RqIEiCOIySvLymLfxf8mop1VCQ8jw" alt="">
</div>
</body>
</html>
