<html>
<head>
  <title>Div example</title>
</head>
<body>

<style type="text/css"> 
.left1 {
  float: left;
  width: 120px;
  padding: 10px;
  border: 1px solid;
}

.left2 {
  float: left;
  width: 120px;
  padding: 10px;
  border: 1px solid;
  clear: left;
}
</style>

<div class="left1">
  1
</div>

<div class="left2">
  2
</div>


</body>
</html>