The best solution for my case was to work with UDP:

udpClient = new UdpClient();
endPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 99999); 
byte[] data = Encoding.UTF8.GetBytes(dataToSend);
udpClient.Send(data, data.Length, endPoint);
Debug.Log("Sent data to JavaScript server: " + dataToSend);