Jumping only once (2D)

Questions & Answers
1

hey! I am a noob when coming to coding, I still don’t know very much about C#, and I am having the trouble of my player only jumping once
if I hit space again when it gets in the ground, it doesn’t jump again

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Player : MonoBehaviour {

	public float Speed;
	public float JumpForce;

public bool isJumping;
public bool doubleJump;

	private Rigidbody2D rig;

	// Use this for initialization
	void Start () {
		rig = GetComponent<Rigidbody2D>();
	}
	
	// Update is called once per frame
	void Update () {

		Move();
		Jump();

	}

	void Move () {
		Vector3 movement = new Vector3(Input.GetAxis("Horizontal"), 0f, 0f);
		transform.position += movement * Time.deltaTime * Speed;
	}

	void Jump () {
		if(Input.GetButtonDown("Jump")) 
        {
            if(!isJumping){
                			rig.AddForce(new Vector2(0f, JumpForce), ForceMode2D.Impulse);
                            doubleJump = true;
            }else{
                if(doubleJump){
                    rig.AddForce(new Vector2(0f, JumpForce), ForceMode2D.Impulse);
                            doubleJump = false;
                }
            }

			}
		}
        void OnCollisionEnter2D(Collision2D collision){
            if(collision.gameObject.layer == 8)
            {
                isJumping = false;
            }
        }
        
        void OnCollisionExit2D(Collision2D collision){
            if(collision.gameObject.layer == 8){
                isJumping = true;
            }
        }
	}

This is the code!! Many thanks if anyone can help me <33

2

@Aserli maybe delete the void OnCollisionExit2D(Collision2D collision) I dont think its necessary

3

just remember to tag the floor as “Floor”

    Rigidbody2D rigBody;
    public float jumpSpeed = 10f;
    bool isGrounded;
    // Start is called before the first frame update
    void Start()
    {
        isGrounded = true;
        rigBody = GetComponent<Rigidbody2D>();
    }
    // Update is called once per frame
    void Update()
    {
        if (Input.GetButtonDown("Jump") && isGrounded)
        {
                GetComponent<Rigidbody2D>().AddForce(new Vector2(0, 
         jumpSpeed), ForceMode2D.Impulse);
                isGrounded = false;
        }
    }

    void OnCollisionEnter2D(Collision2D other)
    {
        if (other.gameObject.tag == "Floor" && isGrounded == false)
        {
            isGrounded = true;
        }
    }