Simple Jump script

I need a simple jump script for a 2d game.

#pragma strict
var mySpeed = 100;
function Start () {
InvokeRepeating("Multiplier", 0, .1);
}

function Update () {

	
	
	 GetComponent.<Rigidbody2D>().velocity = Vector2(mySpeed,0);
	 
	 if (Input.GetButtonDown ("Space"))
	 {
	    //Jump script should go here
	 }
	 
	 
	 }
	 
function Multiplier ()
{
	mySpeed++;
}

I am relatively new to unity so please give me any suggestions in changing my scripts.

Follow the excellent official live training:
http://unity3d.com/learn/tutorials/modules/beginner/live-training-archive/creating-a-basic-platformer-game