<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container main-wrap">
<h1>Awesome CSS Preloaders</h1>
<div class="row">
<div class="col-md-3 bg">
<div class="loader" id="loader-2">
<span></span>
<span></span>
<span></span>
</div>
</div>
<div class="col-md-3 bg">
<div class="loader" id="loader-4">
<span></span>
<span></span>
<span></span>
</div>
</div>
<div class="col-md-3 bg">
<div class="loader" id="loader-1"></div>
</div>
<div class="col-md-3 bg">
<div class="loader" id="loader-6">
<span></span>
<span></span>
<span></span>
<span></span>
</div>
</div>
<div class="col-md-3 bg">
<div class="loader" id="loader-3"></div>
</div>