JavaScript controll var in C#

Hi, now i have a big problem with my code :( so...

i have two scripts, in Java script and C#

but what i want to do here is that ...

JavaScript

 function Update () {
 
     scoreText.text = "" + score;
     // Level  1
         if(score > 20) {
         Xscore = 3;
         cadere.speed = 11;
         }

CSharp Code:

 using UnityEngine;
 using System.Collections;
 
 public class spawn : MonoBehaviour
 {
     public GameObject[] hazards;
     public Vector3 spawnValues;
     public int hazardCount;
     public float spawnWait;
     public float startWait;
     public float waveWait;
     
     
     void Start ()
     {
         StartCoroutine (SpawnWaves ());
     }
     
     IEnumerator SpawnWaves ()
     {
         yield return new WaitForSeconds (startWait);
         while (true)
         {
             for (int i = 0; i < hazardCount; i++)
             {
                 GameObject hazard = hazards [Random.Range (0, hazards.Length)];
                 Vector3 spawnPosition = new Vector3 (Random.Range (-spawnValues.x, spawnValues.x), spawnValues.y, spawnValues.z);
                 Quaternion spawnRotation = Quaternion.identity;
                 Instantiate (hazard, spawnPosition, spawnRotation);
                 yield return new WaitForSeconds (spawnWait);
             }
             yield return new WaitForSeconds (waveWait);
             
         }
     }
     
 }

ok now, in JS script i have an "if" witch increase the speed of the game but...i want to change in same time with this "if" in CSharp var named "spawnWait"

Sorry for my bad en..