Distance between two points

gistfile1.js

var getDistanceFromLatLonInKm = function(lat1, lon1, lat2, lon2) {
    var R = 6371,
        dLat = deg2rad(lat2 - lat1),
        dLon = deg2rad(lon2 - lon1),
        a = Math.sin(dLat/2) * Math.sin(dLat/2) +
            Math.cos(deg2rad(lat1)) * Math.cos(eg2rad(lat2)) *
            Math.sin(dLon/2) * Math.sin(dLon/2),
        c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a)),
        d = R * c;

    return d;
};

var deg2rad = function(deg) {
  return deg * (Math.PI/180);
};