private var timer = 0.0;
 var bobbingSpeed = 0.18;
 var bobbingAmount = 0.2;
 var midpoint = 2.0;

 function Update () {
    waveslice = 0.0;
    horizontal = Input.GetAxis("Horizontal");
    vertical = Input.GetAxis("Vertical");
    if (Mathf.Abs(horizontal) == 0 && Mathf.Abs(vertical) == 0) {
       timer = 0.0;
    }
    else {
       waveslice = Mathf.Sin(timer);
       timer = timer + bobbingSpeed;
       if (timer > Mathf.PI * 2) {
          timer = timer - (Mathf.PI * 2);
       }
    }
    if (waveslice != 0) {
       translateChange = waveslice * bobbingAmount;
       totalAxes = Mathf.Abs(horizontal) + Mathf.Abs(vertical);
       totalAxes = Mathf.Clamp (totalAxes, 0.0, 1.0);
       translateChange = totalAxes * translateChange;
       transform.localPosition.y = midpoint + translateChange;
    }
    else {
       transform.localPosition.y = midpoint;
    }
 }