<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style type="text/css">
div {
background: url("京东LOGO.png");
width: 168px;
height: 81px;
}
div:hover{
opacity: 0.5;
}
</style>
</head>
<body>
<div></div>
</body>
</html>
原文：http://www.cnblogs.com/gujinshu-wangdan/p/5574114.html