Leaflet demo

For update marker position

HTML

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

CSS

#map {
    height: 500px;
    width: 100%;
}

JavaScript

var map = L.map('map').setView([51.505, -0.09], 13);

L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
    attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
}).addTo(map);