script.js

let origBoard;
let huPlayer = "x";
let aiPlayer = "O";

const winCombos = [
    [0,1,2],
    [3,4,5],
    [6,7,8],
    [0,3,6],
    [1,4,7],
    [2,5,8],
    [0,4,8],
    [2,4,6]
];

const cells = document.querySelectorAll(".cell");
startGame();

function startGame() {
    document.querySelector(".endgame").style.display = "none";
    origBoard = Array.from(Array(9).keys());
for (let i = 0; i < cells.length; i++) {
    cells[i].innerText = "";
    cells[i].style.removeProperty("background-color");
    cells[i].addEventListener("click", turnClick, false);
}};

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

function turn(squareId, player){
    origBoard[squareId] = player;
    document.getElementById(squareId).innerText = player;
}