Problem with gravity with regidbody.

Hey guys, i have a very big problem in my Unity. I saw some videos that show me how to grab an object. An how to put it down again. So my problem is that after I learned to "hold" an object, and release it. It is still on mid air. I tried to use regidbody, but no matter what i do. I can't figure it out. Hope you will help me from Jaani.

Here is my script:

 var onhand : Transform;
 
 function Update () {
 
 }
 
 function OnMouseDown () {
 GetComponent.().useGravity = false;
 this.transform.position = onhand.position;
 this.transform.parent = GameObject.Find("FPSController").transform;
 this.transform.parent = GameObject.Find("FirstPersonCharacter").transform;
 }
 
 function OnMouseUp () { 
 this.transform.parent = null; 
 GetComponent.().UseGravity = true;
 }