codice:
     for(i=0;i<routes.length;i++){
            var request = {
                origin:routes[i].origin, 
                destination:routes[i].destination,
                travelMode: google.maps.DirectionsTravelMode.DRIVING,
                unitSystem: google.maps.UnitSystem.METRIC
            };
        
            var polylineOptions={};
            polylineOptions.strokeColor=routes[i].color;

            directionsService.route(request, routeCallback(polylineOptions));
      }

function routeCallback(polylineOptions){
   return function(response, status) {
            if (status == google.maps.DirectionsStatus.OK)
            {
              new google.maps.DirectionsRenderer({
                map: mapObject,
                directions: response,
                polylineOptions: polylineOptions
              });
            }
            else $("#error").append("Impossibile recuperare il percorso
");
    }
}