Character strafing problem (javascript)

I'm having trouble getting my character to strafe. I've currently got the following script working so I can run forward/backwards and also rotate around using the mouse. It's for a top-down game.

 > > public static var speed = 10.0; var rotatationSpeed = 0.0; private var
 > curSpeed = 0.0;
 > 
 > function Start () {
 > 
 > speed = 10;
 > 
 > }
 > 
 > function Update () { // Rotate around
 > y-axis var newRotation =
 > Input.GetAxis("Mouse X") *
 > rotatationSpeed; transform.Rotate(0,
 > newRotation * Time.deltaTime, 0); //
 > Calculate speed var newSpeed =
 > Input.GetAxis("Vertical") * speed; if
 > (Input.GetKey("left shift")) newSpeed
 > *= 1.5; // Move the controller var controller : CharacterController =
 > GetComponent (CharacterController);
 > var forward =
 > transform.TransformDirection(Vector3.forward);
 > controller.SimpleMove(forward *
 > newSpeed);
 > 
 > if (cGUI.health <1) speed = 0;
 > 
 > if (cGUI.health <1) rotatationSpeed =
 > 0;
 > 
 > var up=
 > transform.TransformDirection(Vector3.up);
 > controller.SimpleMove(forward *
 > newSpeed); // Update the speed in the
 > Animation script
 > SendMessage("SetCurrentSpeed",
 > newSpeed,
 > SendMessageOptions.DontRequireReceiver);
 > SendMessage("SetCurrentLean",
 > Input.GetAxis("Horizontal"),
 > SendMessageOptions.DontRequireReceiver);
 > 
 > } @script RequireComponent
 > (CharacterController)

Any help would be fantastic :)