如何从已删除的元素中控制台记录 innerText？

Question

在我的updateCartTotal() function 中，我想console.log记录从购物车中删除的元素。

每次按下删除按钮时，我都希望它打印出item和price 。 但是，每当我这样做时，它都会返回未定义。 在某些情况下，它只能识别 1 个项目。 我认为我的 JavaScript 代码没有问题，而可能是我的 HTML

const updateCartTotal = () => {
    var cartItemContainer = document.getElementsByClassName('cart-items')[0]
    var cartRows = cartItemContainer.getElementsByClassName('cart-row')

    for(var i = 0; i < cartRows.length; i++){
        var cartRow = cartRows[i];
        var itemElement= cartRow.getElementsByClassName('cart-item')[0].innerHTML
        var priceElement = cartRow.getElementsByClassName('cart-price')[0].innerHTML
        var quantityElement = cartRow.getElementsByClassName('cart-quantity-input')[0]

        var item = itemElement.innerText
        var price = priceElement.innerText
        // var quantity = quantityElement.value
        console.log(item, price)
    }
}

<section class="container shopping-cart">
    <div class="title">Cart</div>
    <div class="cart-row">
        <span class="cart-item cart-header cart-column">ITEM</span>
        <span class="cart-price cart-header cart-column">PRICE</span>
        <span class="cart-quantity cart-header cart-column">QUANTITY</span>
    </div>
    <div class="cart-items">
        <div class="cart-row">
            <div class="cart-item">
                <span class="cart-item-title">Item 1</span>
            </div>
            <span class="cart-price ">$14.99</span>
            <div class="cart-quantity-input">
                <input type="number" value="1">
                <button class="btn btn-danger ml-5" type="button">REMOVE</button>
            </div>
        </div>
        <div class="cart-row">
            <div class="cart-item">
                <span class="cart-item-title ">Item 2</span>
            </div>
            <span class="cart-price">$79.99</span>
            <div class="cart-quantity-input">
                <input type="number" value="2">
                <button class="btn btn-danger ml-5" type="button">REMOVE</button>
            </div>
        </div>
    </div>
</section>

Answer 1

我看不到您当前的代码是如何根据按钮单击来控制台记录值的。 所以我创建了 function removeItem() 来实现您想要的功能。 使用此解决方案将功能添加到您的代码中。

请参阅代码笔以获取解决方案。

https://codepen.io/ianroskow/pen/WNeagXQ

在删除按钮的 onclick 上，我传递上下文，然后遍历 dom 以控制台记录所需的值。

我使用最接近找到父节点，并使用查询选择器找到子节点。

https://developer.mozilla.org/en-US/docs/Web/API/Element/closest

https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelector

 const updateCartTotal = () => { var cartItemContainer = document.getElementsByClassName('cart-items')[0] var cartRows = cartItemContainer.getElementsByClassName('cart-row') for(var i = 0; i < cartRows.length; i++){ var cartRow = cartRows[i]; var itemElement= cartRow.getElementsByClassName('cart-item')[0].innerHTML var priceElement = cartRow.getElementsByClassName('cart-price')[0].innerHTML var quantityElement = cartRow.getElementsByClassName('cart-quantity-input')[0] var item = itemElement.innerText var price = priceElement.innerText // var quantity = quantityElement.value console.log(item, price) } } function removeItem(element){ const cartRow = element.closest(".cart-row"); console.log(cartRow.querySelector(".cart-item-title").innerHTML); console.log(cartRow.querySelector(".cart-price").innerHTML); cartRow.parentNode.removeChild(cartRow); }

 <section class="container shopping-cart"> <div class="title">Cart</div> <div class="cart-row"> <span class="cart-item cart-header cart-column">ITEM</span> <span class="cart-price cart-header cart-column">PRICE</span> <span class="cart-quantity cart-header cart-column">QUANTITY</span> </div> <div class="cart-items"> <div class="cart-row"> <div class="cart-item"> <span class="cart-item-title">Item 1</span> </div> <span class="cart-price ">$14.99</span> <div class="cart-quantity-input"> <input type="number" value="1"> <button class="btn btn-danger ml-5" onclick="removeItem(this)" type="button">REMOVE</button> </div> </div> <div class="cart-row"> <div class="cart-item"> <span class="cart-item-title ">Item 2</span> </div> <span class="cart-price">$79.99</span> <div class="cart-quantity-input"> <input type="number" value="2"> <button class="btn btn-danger ml-5" onclick="removeItem(this)" type="button">REMOVE</button> </div> </div> </div> </section>

Answer 2

item和price不会是元素。 它们是表示元素的 innerHTML 的字符串。
要获取商品名称，只需使用cartRow.getElementsByClassName('cart-item -title ')[0].innerHTML 。
要获取价格，请使用cartRow.getElementsByClassName('cart-price')[0].innerHTML 。

不要使用 innerText，因为这会导致错误，因为item和price已经是字符串。

 const updateCartTotal = () => { var cartItemContainer = document.getElementsByClassName('cart-items')[0] var cartRows = cartItemContainer.getElementsByClassName('cart-row') for (var i = 0; i < cartRows.length; i++) { var cartRow = cartRows[i]; var item = cartRow.getElementsByClassName('cart-item-title')[0].innerHTML var price = cartRow.getElementsByClassName('cart-price')[0].innerHTML var quantity = cartRow.getElementsByClassName('cart-quantity-input')[0] console.log(" Item: " + item + "\n" + "Price: " + price) } } updateCartTotal();

 <section class="container shopping-cart"> <div class="title">Cart</div> <div class="cart-row"> <span class="cart-item cart-header cart-column">ITEM</span> <span class="cart-price cart-header cart-column">PRICE</span> <span class="cart-quantity cart-header cart-column">QUANTITY</span> </div> <div class="cart-items"> <div class="cart-row"> <div class="cart-item"> <span class="cart-item-title">Item 1</span> </div> <span class="cart-price ">$14.99</span> <div class="cart-quantity-input"> <input type="number" value="1"> <button class="btn btn-danger ml-5" type="button">REMOVE</button> </div> </div> <div class="cart-row"> <div class="cart-item"> <span class="cart-item-title">Item 2</span> </div> <span class="cart-price">$79.99</span> <div class="cart-quantity-input"> <input type="number" value="2"> <button class="btn btn-danger ml-5" type="button">REMOVE</button> </div> </div> </div> </section>