javascript - 如何用纯javascript再次删除该类

Question

我正在创建一个内存游戏，当我单击游戏的卡片时，我会向其中添加一个类。我希望当两张卡片翻转时删除类(class)。问题是我无法删除/替换我动态创建的class。尝试过 classList.remove()/classList.add() ...

const titleId = document.querySelector(".page-header");
const cardId = document.querySelectorAll(".card");
var cardCounter = 0;

// give the clicked card a class of .card-flipped
// when 2 cards are flipped, activate the function flipCardBack
for (let i = 0; i < cardId.length; i++) {
cardId[i].addEventListener('click', function () {
    cardId[i].classList.add("card-fliped");
    cardCounter ++;

    if (cardCounter === 2){
        cardCounter = 0;
        setTimeout(flipCardBack, 2500);
        }

    });
}

// trying to remove the added class .card-flipped (currently not working)

function flipCardBack() {
let dynamicClassSelector = document.querySelectorAll(".card-fliped");
dynamicClassSelector.classList.remove("card-flipped");
}

我收到的错误消息如下:

Uncaught TypeError: Cannot read property 'remove' of undefined at flipCardBack.

Answer 1

querySelectorAll 返回一个元素列表，如果要删除该类，则必须循环遍历此列表并从每个元素中删除该类，下面是一个示例:

function flipCardBack() {
  document.querySelectorAll(".card-fliped").forEach(element => {
    element.classList.remove("card-fliped");
  })
}

正如@Andreas提到的，你也有一个拼写错误，你使用了card-fliped和card-flipped(有一个和两个p s)。