【border_bottom】
<!DOCTYPE html>
<html>
<head>
<style type='text/css'>
.clear_dotted {
width: 200px;
height: 5px;
border-bottom: 1px dotted black;
}
.merged_dotted {
width: 200px;
height: 5px;
border-bottom: 1px dotted black;
}
</style>
</head>
<body>
<html>
<body>
<div class="clear_dotted"></div>
<br></br>
<div class="merged_dotted"></div>
</body>
</html>
</body>
</html>
