Rapid Fire Problem

I have crated a split screen game in witch players shoot at each other a lose lives. The problem is that the player can just push fire rapidly to kill the player. Can you help me make a script that stop the player for continuously pressing the fire button? This is the script I have.

var speed = 3.0;
var rotateSpeed = 3.0;
var BulletPrefab:Transform;

function Update ()

{
var controller : CharacterController = GetComponent(CharacterController);

//Rotate around y - axis
transform.Rotate(0, Input.GetAxis ("Horizontal") * rotateSpeed, 0);

// Move forward / backward
var forward = transform.TransformDirection(Vector3.forward);
var curSpeed = speed * Input.GetAxis ("Vertical");

controller.SimpleMove(forward * curSpeed);

if(Input.GetButtonDown("Jump"))
{
	var bullet = Instantiate(BulletPrefab, GameObject.Find("spawnPoint").transform.position, 	Quaternion.identity);
	bullet.rigidbody.AddForce(transform.forward * 3000);
}

}

@script RequireComponent(CharacterController)

Do you want to insert a time delay among two shoots? In that case,

var rate : float = 0.5;
private var rate_time : float;

if(Input.GetButtonDown("Jump") && Time.time > rate_time)
{
    rate_time = Time.time + rate;
    var bullet = Instantiate(BulletPrefab, GameObject.Find("spawnPoint").transform.position,   Quaternion.identity);
    bullet.rigidbody.AddForce(transform.forward * 3000);
}

This is the modification of the shooting part, and it will add a delay of an half second duration among two shoots. Just mantain the rest as is, concerning movements and rotation.

Thanks for the help but it still can pressed rapidly. Is there away to not make it shoot if an the object is already exists?