A simple example of Leaflet.js using Mapbox tiles.
Modified http://d3js.org/d3.v3.min.js to a secure url
Modified http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js to a secure url
https://d3js.org/d3.v3.min.js
https://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js