Leaflet Multiple Markers example

HTML

<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.css">
<script src="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.js"></script>
 <div id="map"></div>

CSS

html {
    height:100%;
    min-height100%;
}
body {
    
    padding:0;
    height:100%;
    min-height:100%;
    
}

#map { 
    
   width:100%; 
   height: 100%; 
}

JavaScript

var map = L.map('map').setView([51.5, -0.09], 3);    
        var markers = [];
        for (var i=0; i<5000; i++){
          lat = Math.floor(Math.random()*88) + 1;
          lat *= Math.floor(Math.random()*2) == 1 ? 1 : -1;
            
          lng = Math.floor(Math.random()*88) + 1;
          lng *= Math.floor(Math.random()*2) == 1 ? 1 : -1;
            
          marker = new L.marker([lat, lng]);
          markers.push(marker);
       
      }
      markerGroup = L.layerGroup(markers);
      markerGroup.addTo(map);