Why doesn't this do anything?

I'm trying to get a hang of the basics, I know Lua really well and I was hoping to use what I've learned there to help me learn Java script, (or in this case Unity Script).

So what I plan to do first is a simple 2D game where you roll along on a flat ground, jump to dodge rocks. Simple. So my first step to my grand and magnificent game that is sure to make me millions of dollars, is to figure out how to jump.

I have this so far and nothing happens:

 #pragma strict
 var jump : bool = false;
 function Start () {
 
 }
 function FixedUpdate () {
     if (Input.GetKeyDown(KeyCode.Space)) {
         jump = true;
     }
 }
 function Update () {
     if (jump) {
         Debug.Log('Jump!');
         jump=false;
     }
 }