<div id="map"></div>
*{padding:0; margin:0;}
html, body, #map{width:100%; height:100%; background:#dfdfdf}
// create map
var map = new L.Map('map', {
  center: new L.LatLng(52.520, 13.385),
	zoom: 10,
  zoomControl: false,
  dragging: false,
  scrollWheelZoom: false,
  doubleClickZoom: false,
  boxZoom: false,
  tap: false
}),
  // add geojson    
  geoLayer = L.geoJson(geojson.geometries).addTo(map),
  // color scale from http://colorbrewer2.org
  colors = ['#eff3ff', '#c6dbef', '#9ecae1', '#6baed6', '#4292c6', '#2171b5', '#084594'];

// set base styles
geoLayer.setStyle({
  fillOpacity: 1,
  color: 'white',
  weight: 1
});

updateColors();

// sets color of each layer randomly
function updateColors(){
  geoLayer.eachLayer(function(layer){
    var col = colors[~~(Math.random() * colors.length)];
    layer.setStyle({fillColor: col});
  });
  
  setTimeout(updateColors, 1500);
}

External CSS

  1. https://cdn.leafletjs.com/leaflet-0.6.4/leaflet.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.6.4/leaflet.js
  2. https://codepen.io/moklick/pen/XbjmBQ