code: function(obj, event, callback) {
  		// Use jQuery to handle DOM events.
  		if(underscore.isElement(obj) && $){return $(obj).on(event, callback); }
  
  		// Use internal handler for pubsub
  		if(this.isString(obj)) {callback = event; event = obj; obj = this; }
  
  		// Ensure a container is available for all events.
  		if(!this.isObject(obj.__event_handlers)){ obj.__event_handlers = {}; }
  		// Ensure a handler is available for this particular event.
  		if (!(event in obj.__event_handlers)) {
  			// Using a memory callback
  			obj.__event_handlers[event] = underscore.Callbacks("memory");
  		}
  		obj.__event_handlers[event].add(callback);
  		return this;
  	}
docs: ### on*([object, ]event, callback)* Register a function to get called when a certain event is published. Any event handlers attached after an event has been triggered at least once will immediately be called with the most recently triggered value.