EventEmitter.js

<script src="event_emitter.js"></script>

var User = function(){
  new EventEmitter().apply(this);
  this.name = '';
};

var user = new User();
user.name = 'shokai';
user.on('go', function(data.place){
  alert(user.name+' -> '+data.place);
});

user.emit('go', {place: 'mountain'}); // "shokai -> mountain"

user.once('eat', function(data){
  alert(user.name+' -> eat '+data.what+' at '+data.where);
});

user.emit('eat', {what: 'BEEF', where: 'zanmai'}); // "shokai -> eat BEEF at zanmai"
user.emit('eat', {what: 'Ramen', where: 'marutomo'}); // do not call. call only first time.

user.removeListener('eat');
user.removeListener(id);

user.on('*', function(event_name, data){
  console.log(event_name + ' was called');
  console.log(data);
});