<html>
<head>
<title>Div example</title>
</head>
<body>
<style type="text/css">
.container {
width: 100%;
border: 1px dotted;
clear: left;
float: left;
}
.left {
float: left;
width: 120px;
height: 40px;
border: 1px solid;
text-align: center;
}
.right {
float: right;
width: 120px;
height: 40px;
border: 1px solid;
text-align: center;
}
</style>
<div class="container">
<div class="left">
1
</div>
</div>
<div class="left">
3
</div>
<div class="right">
2
</div>
</body>
</html>