Faye Using Javascript in Rails

I'm new to installing faye I'm using some JavaScript but I can't understand how this is actually working. Can anybody explain please ? here is JavaScript that I'm using :

window.client = new Faye.Client('/faye');

client.addExtension({
  outgoing: function(message, callback) {
    message.ext = message.ext || {};
    message.ext.csrfToken = $('meta[name=csrf-token]').attr('content');
    return callback(message);
  }
});

jQuery(function() {
  var chat_room, error;

  chat_room = $('#chat-room-id').val();
  try {
    client.unsubscribe('/events/'+chat_room+'/ideas');
  } catch (error) {
    if (typeof console !== "undefined" && console !== null) {
      console.log("Can't unsubscribe.");

    }
  }
  return client.subscribe('/events/'+chat_room+'/ideas', function(payload) {
    alert(payload)
    if (payload.message) {
      return $('#comments').find('.media-list').prepend(payload.message);
    }
  });
});