i'm making a 2d game, the player can endlessly jumply please help!

using UnityEngine; using System.Collections;

public class robotControler : MonoBehaviour { //how fast the robot con move public float topSpeed = 10f; //tell the sprite wich way to face bool facingRight = true;

 //get rederence to animator
 Animator anim;

 //not grounded
 bool grounded = false;

 //transforms at robots foot to see if he is touching the ground
 public Transform groundCheck;

 //how big the circle is going to be when we check the distance
 float groundRadius = 0.2f;

 // force of the jump
 public float jumpForce = 700f;

 //what layer is cnsidered the ground
 public LayerMask whatIsGround;

 //varible to check double jump
 bool doubleJump = false;

 void Start()
 { 
     anim = GetComponent<Animator>();
 }

 //physics in fixed update
 void FixedUpdate()
 {
     //true or false did the ground transform hit the what is ground with the ground radius
     grounded = Physics2D.OverlapCircle(groundCheck.position, groundRadius, whatIsGround);

     //tell the animator that we are grounded
     anim.SetBool("Ground", grounded);

     //reset double jump
     if (grounded)
         doubleJump = false;

     //how fast we are moving down from the rigif body
     anim.SetFloat("vSpeed", GetComponent<Rigidbody2D>().velocity.y);

     //get move direction
     float move = Input.GetAxis("Horizontal");

     //add velocity to ridgidbody in move direction * our speed
     GetComponent<Rigidbody2D>().velocity = new Vector2(move * topSpeed, GetComponent<Rigidbody2D>().velocity.y);

     //new
     anim.SetFloat("Speed", Mathf.Abs(move));

     //if we're facing the negative direction and not facing the right, flip
     if (move > 0 && !facingRight)
         Flip();
     else if (move < 0 && facingRight)
         Flip();
 }

 void Update()
 {
     if ((grounded || !doubleJump) && Input.GetButtonDown("Jump"))
     {
         anim.SetBool ("Ground", false);

         GetComponent<Rigidbody2D> ().AddForce (new Vector2 (0, jumpForce));

         if (!doubleJump && !grounded)
             doubleJump = true;
     }
 }

 void Flip()
 {
     //saying we are facing the opersite way
     facingRight = !facingRight;

     //get the local scale
     Vector3 theScale = transform.localScale;

     //flip on the x axis
     theScale.x *= -1;

     //apply that to the local scale
     transform.localScale = theScale;
 }

}