Setting an animation with the mouse wheel

Hello!

I'm trying to make a script that set an animation forward or backward on her timeline with the mouse wheel.
The scrip in question is on the character, and the animation on a parent gameobject.

For the moment, I have this but, of course, it does not work.

using UnityEngine;
using System.Collections;

public class AnimationControl : MonoBehaviour {
// Use this for initialization
void Start () {
}

// Update is called once per frame

void Update () {
if(Input.GetAxis("Mouse ScrollWheel") > 0) { animation["AnimationJourNuit"].time ++; }

else if(Input.GetAxis("Mouse ScrollWheel") < 0) { animation["AnimationJourNuit"].time --; }
animation["AnimationJourNuit"].speed = 0.0;
animation.Play(AnimationJourNuit);
}
}

I'm novice in code, and I don't know if I'm far or near the solution.
Please tell me where I'm wrong and what should I do to correct the issue.