text: function haversine() {
         var radians = Array.prototype.map.call(arguments, function(deg) { return deg/180.0 * Math.PI; });
         var lat1 = radians[0], lon1 = radians[1], lat2 = radians[2], lon2 = radians[3];
         var R = 6372.8; // km
         var dLat = lat2 - lat1;
         var dLon = lon2 - lon1;
         var a = Math.sin(dLat / 2) * Math.sin(dLat /2) + Math.sin(dLon / 2) * Math.sin(dLon /2) * Math.cos(lat1) * Math.cos(lat2);
         var c = 2 * Math.asin(Math.sqrt(a));
         return R * c;
  }
  console.log(haversine(36.12, -86.67, 33.94, -118.40));
  