Change static variable in JS through Csharp

I am working on a script to change a variable of a JS script through a C#

my JS:

static var counter : int = 10 + counter2; 
static var counter2 : int = PlayerPrefs.GetInt("CubeCoin");

function Update(){
CubeCoin.counter = 10 + counter2;


my C#

using UnityEngine;
using System.Collections;

public class CSharp2 : MonoBehaviour 
	//create a variable to access the JavaScript script
	static CubeCoin jsScript; 

	void Awake()
		//Get the JavaScript component
		jsScript = this.GetComponent<CubeCoin>();

	void OnGUI()
		if (GUI.Button (new Rect (15, Screen.height-Screen.height/5, Screen.width/6, Screen.height/13), "bla")) {
			jsScript.counter2 +=1;

but this don`t work.
i got error CS0176 Static member CubeCoin.counter2 cannot be accessed with an instance reference, qualify it with a type name instead.
how can i fix that ?
and i have to leave the variable static.

A static member belongs to the class itself, and not to a particular object that has that type. So, it’s incorrect to try an access a particular instance of that class through GetComponent(). Instead, you need to use the class:

// replacement for line 19
CubeCoin.counter2 += 1;

If you are not familiar with static members, take a look at the GameObject class:

Lots of the variables apply to regular game objects in your scene. Near the bottom of the page is a section titled “Static Functions”. This section describes the static functions of the GameObject class. If you look at the documentation for the Find() function you’ll see that you use GameObject.Find() - that’s to say you use the class name and not a variable set to a particular game object.