(2D) character jumping problem [is grounded detection, rigidbody2d]

Hello. There you can see my script. I try to make a 2D Jump and Run game. But sometimes if i hold the space button (for jumping) my character makes a unwanted “mega jump”. I think because my character is grounded too long and the script adds the force to the 2d rigidbody two or more times. Can someone help me ?

using UnityEngine;
using System.Collections;

public class CharacterController : MonoBehaviour {
    private Rigidbody2D rb;
      public float JumpForce = 1000;
    public bool isGroundet = false;
    public bool Jump = false;
    public Transform [] groundCheck;
    public LayerMask whatIsGround;
  
     
     // Use this for initialization
    void Start () {
        rb = gameObject.GetComponent<Rigidbody2D>();
   	}

  

        void FixedUpdate () {
        
        rb.velocity = new Vector2(Speed, rb.velocity.y);

        if (Input.touchCount > 0 || Input.GetKey(KeyCode.Space) || Input.GetMouseButtonDown(0))
        {      
               Jump = true; 
        }

          isGroundet = false;
        
        
        if (Physics2D.OverlapCircle(groundCheck[0].position, .15f, whatIsGround))
          {
            isGroundet = true;
        }

            if (Jump && isGroundet&&rb.velocity.y<JumpForce)
             {
            rb.AddForce(Vector2.up * JumpForce);
          
            Jump = false;
        }   
          
        
            
    }
        

      
}

Try to reset a valocity before:

rb.velocity = new Vector2(rb.velocity.x, 0f);

and then add the force:

rb.AddForce(Vector2.up * JumpForce);

Or simplify all of it by:

rb.velocity = new Vector2(rb.velocity.x, JumpForce);

For best results, it’s handy to keep in mind that inputs are registered during Update(). This means that OnGUI(), with double the framerate of Update(), will register inputs twice per frame and FixedUpdate(), not matching the timing of Update(), may occasionally miss inputs.

With that in mind, my example will break input and usage into two sections:

// Updated touch input to be based on when the touch is first applied
// Similarly, updated keyboard input to a GetKeyDown check
void Update()
{
	if ((Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began) || Input.GetKeyDown(KeyCode.Space) || Input.GetMouseButtonDown(0))
	{      
		Jump = true; 
	}
}

void FixedUpdate()
{
	// Multiplied velocity check by 0.95 for safety
	if (Jump && isGroundet && rb.velocity.y < JumpForce * 0.95f)
	{
		// Force applied is immediate.
		rb.AddForce(Vector2.up * JumpForce, ForceMode2D.Impulse);
		
		Jump = false;
	}
}

To note, you would also want to divide your current “JumpForce” by about 50 (default physics step) in order to bring the jumping velocity back down to where you’d want it.

Edit: Whoops, right. Rigidbody2D.