What is "leaflet"

Leaflet is a code Javascript library used to create web mapping applications. It supports most desktop and mobile platforms, supporting HTML5 and CSS3. Along with Openlayers and the Google Maps API, it is one of the most popular Javascript mapping libraries.

Leaflet allows developers with no GIS experience to easily display mosaic web maps hosted on a public server, with optional mosaic overlays. It can load resource data from Geojson files, style them and create interactive layers such as bookmarks with pop-ups when clicked.