倒數計時器

using UnityEngine;
using System.Collections;
using UnityEngine.UI;


public class NewBehaviourScript : MonoBehaviour
{
    public bool timerOn = false;
    float time;
    // Use this for initialization
    void Start()
    {
        time = 3;
        timerOn = false;
    }

    // Update is called once per frame
    void Update()
    {
        Text mytxt3 = GameObject.Find("Canvas/Panel/Text3").GetComponent<Text>();
        if (timerOn == true&& time>0)
        {
            time = time- Time.deltaTime;
            mytxt3.text = time.ToString();

        }
        if(timerOn == true && time < 0)
        {
            time = 0;
            mytxt3.text = time.ToString();
        }
        Text mytxt1 = GameObject.Find("Canvas/Panel/Text").GetComponent<Text>();
        mytxt1.text = System.DateTime.Now.ToString("MM/dd/yyyy");
        Text mytxt = GameObject.Find("Canvas/Panel/Text2").GetComponent<Text>();
        mytxt.text = System.DateTime.Now.ToString("hh:mm:ss");


    }
    public void startB()
    {
        timerOn = true;
    }
    public void stopB()
    {
        if (time == 0)
        {
            Text mytxt3 = GameObject.Find("Canvas/Panel/Text3").GetComponent<Text>();
            time = 3;
            mytxt3.text = time.ToString();
        }
        timerOn = false;
    }

}