GameObject Follow Mouse position

So I'm trying to have a game object follow the mouse position but i was using out dated tutorials and guides so i had to come up with my own code. Sadly i'm kinda stuck because it tells me direction isn't part of unity vector 3?
ray is the original code, but ray won't follow mouse positions, mouseworldposition works fine though.
#pragma strict
var ball:GameObject;
function Start () {

}
private var hits:RaycastHit[];
var hit:RaycastHit;
private var ray:Ray;
function Update () {
var mouseWorldPosition : Vector3 = Camera.main.ScreenToWorldPoint(Input.mousePosition);
ray=Camera.main.ScreenPointToRay(Input.mousePosition);

//Debug.DrawLine(transform.position, mouseWorldPosition, Color.red);
hits=Physics.RaycastAll(Camera.main.transform.position,ray.direction,50);
for (var i = 0;i < hits.Length; i++){
hit = hits;
if(hit.collider.tag=="screen")
{
ball.transform.position=hit.point;
}
}
}

 

dont you need to put this in script tags or on pastebin or something