diff --git a/nginx/public/officeHours.js b/nginx/public/officeHours.js
index 3514c14..5357673 100644
--- a/nginx/public/officeHours.js
+++ b/nginx/public/officeHours.js
@@ -3,6 +3,8 @@ const socket = io.connect("http://localhost:8080", {transports: ['websocket']});
 socket.on('queue', displayQueue);
 socket.on('message', displayMessage);
 
+
+
 function displayMessage(newMessage) {
     document.getElementById("message").innerHTML = newMessage;
 }
diff --git a/src/main/scala/model/OfficeHoursServer.scala b/src/main/scala/model/OfficeHoursServer.scala
index 09ef61b..b2cd3b9 100644
--- a/src/main/scala/model/OfficeHoursServer.scala
+++ b/src/main/scala/model/OfficeHoursServer.scala
@@ -60,10 +60,15 @@ class DisconnectionListener(server: OfficeHoursServer) extends DisconnectListene
 
 class EnterQueueListener(server: OfficeHoursServer) extends DataListener[String] {
   override def onData(socket: SocketIOClient, username: String, ackRequest: AckRequest): Unit = {
-    server.database.addStudentToQueue(StudentInQueue(username, System.nanoTime()))
-    server.socketToUsername += (socket -> username)
-    server.usernameToSocket += (username -> socket)
-    server.server.getBroadcastOperations.sendEvent("queue", server.queueJSON())
+    var usernameList=server.usernameToSocket.keySet
+    if (usernameList.contains(username)) {
+      server.usernameToSocket(username).sendEvent("message","This username has been taken, plz change a username!!  ")
+    }else {
+      server.database.addStudentToQueue(StudentInQueue(username, System.nanoTime()))
+      server.socketToUsername += (socket -> username)
+      server.usernameToSocket += (username -> socket)
+      server.server.getBroadcastOperations.sendEvent("queue", server.queueJSON())
+    }
   }
 }