How do I add a jump function to my current script?

using UnityEngine;
using System.Collections;

public class Player : MonoBehaviour {
	public float speed = 200;
	public float maxSpeed = 5;
	int moving = 0;
	float mouseX = 0;

	// Update is called once per frame
	void Update () {

		if (Input.GetMouseButtonDown (0)) {
				mouseX = 90 * ((Input.mousePosition.x - Screen.width / 2) / (Screen.width / 2)); 
		} else {
				mouseX = 0;
		}

		if (Input.GetKey("right") || mouseX > 0)
		{
			moving = 1;
		}
		else if (Input.GetKey("left") || mouseX < 0)
		{
			moving = -1;
		}
		else
		{
			moving = 0;
		}

		if (moving != 0)
		{
			var velocityX = System.Math.Abs(rigidbody2D.velocity.x);
			
			if (velocityX < .5)
			{
				rigidbody2D.AddForce(new Vector2(moving, 0) * speed);
				
				if (this.transform.localScale.x != moving)
					this.transform.localScale = new Vector3(moving, 1, 1);
			}
			
			if (velocityX > maxSpeed)
				rigidbody2D.velocity = new Vector2(maxSpeed * moving, 0);
		}

	}
}

if (Input.GetKey(“Jump”))
{

       rigidbody.AddForce(Vector3.up*jumpSpeed);
     }