Help! My chatroom doesn't work

in the movie, there’s a XMLSocket, chat
I use if (chat.connect(null, 8080) == false) {…}else{…}
to know if the connection is ok
then, in another frame(I’m already in this frame), here’s the AS:

 
chat.onConnect = function(success){
if (success) {
  disp = "connection succeeded";
 } else {
  disp = "connection failed";
 }
 }
chat.onXML = function(messages){
 var mess = messages.firstChild.firstChild.nodeValue
 disp += mess+"
"
 }
_root.send_bt.onRelease = function() {
 chat.send("<MESSAGE>"+inp+"</MESSAGE>");
 inp = "";
};

disp is a textfield to show the texts, inp is a textfield to say things
everything are ok exept that I can’t see what I write when I click the send_bt button