Leaflet.JS - Open-Source JavaScript Library for Mobile-Friendly Maps

Leaflet.JS is an open source JavaScript Library developed by Vladimir Agafonkin. it's an Open source JavaScript Library to create Mobile friendly interactively Map for Smartphones. The script is only about 31 KB in weight and offered all major features required for Online maps.
Leaflet – JavaScript Library for Mobile Friendly Maps
The script is work seamlessly on all major desktop and mobile platforms out of the box, taking advantage of HTML5 and CSS3 on modern browsers while still being accessible on older ones.
How to Install :

// create a map in the "map" div, set the view to a given place and zoom
var map = L.map('map').setView([51.505, -0.09], 13);

// add an OpenStreetMap tile layer
L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {
    attribution: '© OpenStreetMap contributors'

// add a marker in the given location, attach some popup content to it and open the popup
L.marker([51.5, -0.09]).addTo(map)
    .bindPopup('A pretty CSS3 popup. 
 Easily customizable.')

Features :
  1. Map Layers - Tile layers, Markers, Popups, Vector Layers, Image Layers, WMS Layers, Layer groups, GeoJSON layers
  2. Drag panning with inertia
  3. Zoom Animation
  4. Panning animation
  5. Smooth continuous zoom on modern mobile devices
  6. Tile and popup fade animation
  7. Retina resolution support for tile layers and markers
  8. Pure CSS3 popups and controls for easy restyling the Maps
  9. Image- and HTML-based markers
  10. Custom map projections (with EPSG:4326, EPSG:3857and EPSG:3395 out of the box)
Download - Leaflet JS