<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div class="side_nav" >
<button class="btn btn-primary" id="side_nav">Side Nav</button>
</div>
<div class="d-flex flex-row flex-wrap">
<div class="col-md-3">
<div class="card card-fix">
<div class="card-body">
</div>
</div>
</div>
<div class="col-md-9">
<div class="card card-fix">
<div class="card-body">
</div>
</div>
</div>
</div>
<script>
class side_nav {
constructor() {
$anchor = $('#side_nav');
this.start();
}
start(){
$anchor.click(this, function(e){