DebugTest.cs

using UnityEngine;
using System.Collections;

public class InputTest : MonoBehaviour 
{
	void Update()
	{
		if( Input.GetKeyDown(KeyCode.LeftArrow) )
		{
			GetComponent<Handler>().param.Value += 1;
		}
	}
}

DebugTest.js

#pragma strict

function Start () {
	var handle : Handler = GetComponent(Handler);
	
	ChangeParam(handle.param.Value);
	handle.param.action += ChangeParam;
}

function OnDestroy()
{
	var handle : Handler = GetComponent(Handler);
	handle.param.action -= ChangeParam;
}

function ChangeParam( t : int)
{
	Debug.Log("js:" + t);
}

Handler.cs

using UnityEngine;
using System.Collections;

// Pluginsフォルダに配置

public class Handler : MonoBehaviour {

	public NotificationObject<int> param = new NotificationObject<int>(0);

	void OnDestroy()
	{
		param.Dispose();
	}
}