unity2d javascript jump help

Trying my best at a 2d side scrolling infinite runner, but I cant seem to get the character to jump. When I press space he starts flying up constantly without coming down. Please help me out, and thanks in advance.

#pragma strict

var myForce : float = 25;
var jumpForce : float = 25;

function Start () {

};

function Update () {

	if(Input.GetKeyDown(KeyCode.Space));
		{
			rigidbody2D.AddForce(Vector2.right * jumpForce);
		};
};

function FixedUpdate () {

		rigidbody2D.AddForce(Vector2.right * myForce);

};

turn the “jumpForce” up to like 1000.

var myForce : float = 25;
var jumpForce : float = 1000;
 
function Update () {


if(Input.GetKeyDown(KeyCode.Space));
    {
        rigidbody2D.AddForce(Vector2.up * jumpForce);
    }

}

function FixedUpdate()
 {
            rigidbody2D.AddForce(Vector2.right * myForce);
 }