What to add to this script to control ROF

Here is my shooting script.....

var Bullet : Transform;
function Update () {
    if (Input.GetButton ("Fire1")){
        var bullet = Instantiate(Bullet,GameObject.Find("BulletSpawn").transform.position,Quaternion.identity);
        bullet.rigidbody.AddForce(transform.forward *2000);
        Destroy(bullet.gameObject, 2);
    }
}   

Im new to javascript and I'm trying to learn it. Since I have Input.GetButton its automatic fire, but its way to fast. Can somone show me how to creat a variable in the inspector; in the script, so I can change the Rate of Fire speed for different guns?? Thank you for the time.

Well, you need some sort of timeout to prevent shooting while the gun is "cooling down".

that should do the job:

var Bullet : Transform;
var ROF = 10.0; // Rate of fire in bullets/sec.
private var timeout = 0.0;

function Update () {
    if (Input.GetButton ("Fire1") && Time.time >= timeout){
        var bullet = Instantiate(Bullet,GameObject.Find("BulletSpawn").transform.position,Quaternion.identity);
        bullet.rigidbody.AddForce(transform.forward *2000);
        Destroy(bullet.gameObject, 2);
        timeout = Time.time + 1.0/ROF;
    }
}