tap to move object

hello, I wonder how do I get when I give a tap on the screen my object to move up the place? how do I implement the script to drag?

here's the script:

var object : GameObject;

function Update () {

 for (var touch : Touch in Input.touches){

     var ray = Camera.main.ScreenPointToRay(touch.position);

     var hit : RaycastHit;

     if (Physics.Raycast (ray, hit, 100)) {

         if(touch.phase == TouchPhase.Began || touch.phase == TouchPhase.Moved) {

             var cameraTransform = Camera.main.transform.InverseTransformPoint(0, 0, 0);

             object.transform.position = Camera.main.ScreenToWorldPoint(new Vector3 (touch.position.x, touch.position.y, cameraTransform.z - 0.5));

         }

     }

 }

}