chat.js

//make connection
var socket = io.connect('http://localhost:9000');

//Query DOM
var message = document.getElementById('message');
var handle = document.getElementById('handle');
var btn = document.getElementById('send');
var output = document.getElementById('output');
var feedback = document.getElementById('feedback');

//emit events
btn.addEventListener('click',function(){
  socket.emit('chat',{
      message:message.value,
      handle:handle.value
  });
});

message.addEventListener('keypress',function(){
    socket.emit('typing',handle.value);
});

//listen for events
socket.on('chat',function(data){
    feedback.innerHTML = "";
    output.innerHTML +='<p>'+'<strong>'+ data.handle +' :</strong>'+ data.message +'</p>' 
});
socket.on('typing',function(data){
  feedback.innerHTML = '<p><em>'+data+'is typing...</em></p>'
});