浮动
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>浮动</title>
<style>
div {
width: 200px;
height: 200px;
background-color: blue;
float: left;
}
</style>
</head>
<body>
<div></div>
<div></div>
<div></div>
</body>
</html>

清除浮动
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>清除浮动</title>
<style>
.clearfix:before,
.clearfix:after {
content: "";
display: table;
}
.clearfix:after {
clear: both;
}
.clearfix {
*zoom: 1;
}
.box {
width: 500px;
border: 1px solid black;
margin: 0 auto;
}
.da {
width: 200px;
height: 200px;
background-color: aqua;
float: left;
}
.xi {
float: left;
width: 200px;
height: 200px;
background-color: aqua;
}
.footer {
height: 200px;
background-color: black;
}
</style>
</head>
<body>
<div class="box clearfix">
<div class="da">溯琳</div>
<div class="xi">琳玉</div>
</div>
<div class="footer"></div>
</body>
</html>


ps:图片来自黑马程序员