Leaflet - first step

script.js

var initialCoordinates = [-22.91, -43.20]; // Rio de Janeiro
var initialZoomLevel = 13;

// create a map in the "map" div, set the view to a given place and zoom
var map = L.map('map').setView(initialCoordinates, initialZoomLevel);

// add an OpenStreetMap tile layer
L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {
    attribution: '&copy; Contribuidores do <a href="http://osm.org/copyright">OpenStreetMap</a>'
}).addTo(map);