Consider this example:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<div class="row">
<div class="col-xs-12" style="background-color: black;" >
<div style="width: 50%; height:20px; background-color: red;display: inline-block;"></div>
<div style="width: 50%; height:20px; background-color: red;display: inline-block;"></div>
</div>
</div>
</div>
</body>
</html>
Why the two div
s can't fit in the col? Pretty simple, but it doesn't work.