Attaching Main Camera to a GameObject

I am trying to create a function (in javascript) where if you press a button (R), the main camera will become a child of the game object (the vehicle).

 #pragma strict
 
 public var moveSpeed : float = 10f;
 public var turnSpeed : float = 50f;
 
 
 function Update ()
 {
 
     if(Input.GetButtonDown("R"))
         //main camera to game object here
     
     if(Input.GetKey(KeyCode.UpArrow))
         transform.Translate(Vector3.forward * moveSpeed * Time.deltaTime);
     
     if(Input.GetKey(KeyCode.DownArrow))
         transform.Translate(-Vector3.forward * moveSpeed * Time.deltaTime);
     
     if(Input.GetKey(KeyCode.LeftArrow))
         transform.Rotate(Vector3.up, -turnSpeed * Time.deltaTime);
     
     if(Input.GetKey(KeyCode.RightArrow))
         transform.Rotate(Vector3.up, turnSpeed * Time.deltaTime);
 }