JS中的简单功能不起作用。上交井字游戏

Question

我正在用html + css + js编写简单的井字游戏。我对一个功能有疑问，该功能应该在我的游戏板上的位置1中写一个“ X”。当我单击位置0时，可以看到我的O形弯，但X形弯不起作用。

var gameBoard;
const user = "O";
const ai = "X";
const win = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [6, 4, 2]
]

const box = document.querySelectorAll('.box');
startGame();

function startGame() {
    document.querySelector(".koniec").getElementsByClassName.display = "none";
    gameBoard = Array.from(Array(9).keys());
    for (var i = 0; i < box.length; i++) {
        box[i].innerText = '';
        box[i].style.removeProperty('background-color');
        box[i].addEventListener('click', turnClick, false);
    }
}

function turnClick(square) {
    turn(square.target.id, user)
}

function turn(squareId, player) {
    gameBoard[squareId] = player;
    document.getElementById(squareId).innerText = player;
    console.log(gameBoard[0]);
}

function aiTurn(gameBoard) {
    if(gameBoard[0]=="O"){
        turn(1, ai);
    }
    console.log("asdasd");
}