<link href="//netdna.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<script src="https://cdnjs.cloudflare.com/ajax/libs/openlayers/2.11/lib/OpenLayers.js"></script>
<div id="map" style="height:250px"></div>
map = new OpenLayers.Map("map");
map.addLayer(new OpenLayers.Layer.OSM());
map.zoomToMaxExtent();