problem with simple gameover,gameover when hp reaches 0

I’m trying to get the character deleted when HP reaches zero but nothing happens, what’s going on?

the code:

var GameOver: AudioClip;
function update ()
{
if(HealthVar.Health <= 0)
 Destroy (gameObject);
AudioSource.PlayClipAtPoint(GameOver, transform.position);
}

Create a c# class and put this on any gameObject. Hit play and you will see how is deleted when health reaches 0

public class MyClass : MonoBehaviour{
    public int health;

    public Start()
    {
        health = 100;
    }

    public Update(){
        health -= 0.5f;

        if(health <= 0){
            Destroy(gameObject);
        }
    }
}