浮动以及清除浮动
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
*{margin:0;padding:0;}
ul li{list-style: none;width:150px;float:left;text-align: center;background: #ccc;color:#fff;margin:5px 1px;}
.clear{clear:both;}
.test{width: 200px;height: 200px;background: yellow}
</style>
</head>
<body>
<ul>
<li>Jquery</li>
<li>PHP</li>
<li>JS</li>
<li>JAVA</li>
<li>HTML</li>
</ul>
<div></div>
<div>test1啊</div>
<div>test2</div>
<div>test3</div>
</body>
</html>