Jumping forward in sidescroller

Hi,I need help whit jumping forward in sidescroller.. Right now it only jumps up, but it's sidescroller so I need to make it jump forward and backward like in FPS controller! I am not good scripter so I would be happy if you help me whit it!

My script:

 var speed : float = 3.0;
 var rotateSpeed : float = 3.0;
 private var dead = false;
 private var time = true;
 private var accel = false;
 private var slow = false;
 var slowdown = 0.2;
 var score = 1f;
 var timescale = 1f;
 var acc = 0.2;
 var ReadyToFire = true;
 var ReadyToSlow = true;
 private var moveDirection = Vector3.zero;
 private var grounded : boolean = false;
 var gravity = 20.0;
 var JumpSpeed : float = 10;
 
 
 function timecall(){
 time = false;
 yield WaitForSeconds (1);
 timescale= timescale+1;
 time = true;
 }
 
 function OnControllerColliderHit (hit : ControllerColliderHit)
 {
      if(hit.gameObject.tag == "dead")
      {
          Application.LoadLevel(2);
      }
           if(hit.gameObject.tag == "box")
   
   
   {
      //destroy the ammo box
      Destroy(hit.gameObject);
      score = score+1;
   }
             if(hit.gameObject.tag == "turbo")
   {
      //destroy the ammo box
      Destroy(hit.gameObject);
      speed = speed+6.5;
      yield WaitForSeconds (2.75);
      speed = speed-6.5;
   }
        if(hit.gameObject.tag == "Win")
      {
          Application.LoadLevel(3);
      }
 }
 
 
 function Update () {
 var controller : CharacterController = GetComponent(CharacterController);
 var rigid : Rigidbody = GetComponent(Rigidbody);
 if(grounded){
 
                 if (Input.GetButton("Jump")){
 
                                 moveDirection.y = JumpSpeed;
 
 
 
 
 
                         }   
                     }
                     moveDirection.y -= gravity * Time.deltaTime;
 
                         var flags = controller.Move(moveDirection * Time.deltaTime);
 
                                     grounded = (flags & CollisionFlags.CollidedBelow) != 0;
                  
 
 var right : Vector3 = transform.TransformDirection(Vector3.right);
 var RotateSpeed : float = rotateSpeed * Input.GetAxis ("Horizontal");
 controller.SimpleMove(right * RotateSpeed);
 // Move forward / backward
 var forward : Vector3 = transform.TransformDirection(Vector3.forward);
 var curSpeed : float = speed;
 controller.SimpleMove(forward * curSpeed);
 }
 function LateUpdate()
 {
      if(dead)
      {
          transform.position = Vector3(-0.023, 3.8, -14.89);
          gameObject.Find("Main Camera").transform.position = Vector3(-0.023, 3.8, -14.89);
          dead = false;
      }
 }
 @script RequireComponent(CharacterController)