<link rel="stylesheet" type="text/css" href="http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.css" />
<link rel="stylesheet" type="text/css" href="http://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/0.4.0/MarkerCluster.css" />
<link rel="stylesheet" type="text/css" href="http://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/0.4.0/MarkerCluster.Default.css" />
<script type='text/javascript' src='https://code.jquery.com/jquery-2.1.4.min.js'></script>
<script type='text/javascript' src='http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.js?2'></script>
<script type='text/javascript' src='http://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/0.4.0/leaflet.markercluster.js'></script>
<div id="map" style="width: 100%; height: 440px; border: 1px solid #AAA;"></div>
<script type='text/javascript' src='xxx/markerslist-to-json.php'></script>
<script type='text/javascript' src='xxx/maps/leaf-demo.js'></script>
<script type='text/javascript' src='http://cdnjs.cloudflare.com/ajax/libs/leaflet.markercluster/0.4.0/leaflet.markercluster.js'></script>