Bootstrap Buttons Checkboxes

Checkboxes are shown in the form of buttons.

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
    <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
</head>
<body>
    <div class="btn-group" data-toggle="buttons">
        <label class="btn btn-warning">
            <input type="checkbox" autocomplete="off"> Unchecked Checkbox 1
        </label>
        <label class="btn btn-warning active">
            <input type="checkbox" autocomplete="off" checked> Checked Checkbox
        </label>
        <label class="btn btn-warning">
            <input type="checkbox" autocomplete="off">Unchecked Checkbox 2
        </label>
    </div>
</body>
</html>

Output