Browser and Server Communication Problem - Server only receive One text?

I try to build the website and communicate with Server (not web server), by using unity3D.

The problem is that, when I run both code on unity3d (one is client, other one Server). Both can send/receive test string very well.

[client side will send text:0,1,2,3,4,5,....]

[client side receive text:123,123]

[server side will send test:123,123. if server receive client side data]

[server side receive text:0,1,2,3,4,5,....]

But when I build the [website(client) code] to HTML5 by using Unity3D and run on Firefox browser, the server only receives one text data.

[server side receive the text:0] [client side no receive]

This is website(client) code:

 public class EchoTest : MonoBehaviour {
 // Use this for initialization
     IEnumerator Start () {

     WebSocket w = new WebSocket(new Uri("ws://127.0.0.1:3000")); 
     yield return StartCoroutine(w.Connect());
     w.SendString("0");
     int i = 0;
     while (true)
     {
       string reply = w.RecvString();
       if (reply != null)
       {
         Debug.Log ("Received: "+reply);
         w.SendString(""+i++);
       }
       if (w.error != null)
       {
         Debug.LogError ("Error: "+w.error);
         break;
       }
       yield return 0;
     }    
     w.Close();
   }
 }

This is Server code:

   public class IOWebSocket : MonoBehaviour
   {

   private static int i = 0;
   WebSocketServer server;

   void Start()
   {
     server = new WebSocketServer(3000);
     server.AddWebSocketService<Echo>("/");
    server.Start();     
   }

   void OnDestroy()
   {
     server.Stop();
     server = null;
   }
   }

 // Update is called once per frame

 public class Echo : WebSocketBehavior
 {
   protected override void OnMessage(MessageEventArgs e)
   {
     Sessions.Broadcast("123");
     Debug.Log(System.Text.Encoding.Default.GetString(e.RawData));
   }
 }

I need some help, please.