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));