c# unity mouse over

// A call to OnMouseEnter occurs on the first frame the mouse is 
// over the object.
void OnMouseEnter()
{
  	Debug.Log("Mouse just entered GameObject.");
}

// If your mouse hovers over the GameObject with the script attached, 
// output this message:
void OnMouseOver()
{
    Debug.Log("Mouse is over GameObject.");
}

// Called when the mouse is not any longer over the Collider.
void OnMouseExit()
{
	Debug.Log("Mouse is no longer on GameObject.");
}