原生js实现计算购物车总金额的示例

   <div class="cartMain1" data-id=${Goods_id}>
    <input type="checkbox" class="checkbox" />
    <input type="hidden" class="hiddenVal">
    <div class="cartMsg">
      <img src="${goods_image}" alt="" />
      <div class="cartDetail2">
        <h3>${goods_name}</h3>
        <div class="cartDCont">
          <p class="commonMoney">￥<span class="singlePrice">${goods_price_max}</span></p>
          <div class="count">
            <button class="decrease">-</button>
            <input type="text" class="goodsSum" value=${goods_num} />
            <button class="increase">+</button>
          </div>
        </div>
      </div>
    </div>
  </div>

function getHiddenMoney() {
  let str = 0;
  Array.from(checkboxEl).forEach((item) => {
    if (item.checked == true) {
      str += +item.nextElementSibling.value;
    }
  });
  document.querySelector(".totalPrice").innerHTML = str.toFixed(2);
}

function toHiddenMoney(el) {
  const parent = el.parentnode;

  //获取单价元素
  const singlePrice = +parent.querySelector(".singlePrice").innerHTML;

  //获取商品数量
  const goodsSum = +parent.querySelector(".goodsSum").value;

  //商品总价为
  let totalPriceVal = (singlePrice * goodsSum).toFixed(2);

  //赋值给hidden input框
  el.nextElementSibling.value = totalPriceVal;

  getTotalMoney();
}

  for (let i = 0; i < box.length; i++) {
    box[i].addEventListener("click", function () {
      checkbox.checked = Array.from(box).every((item) => item.checked);
      toHiddenMoney(box[i]);
    });
  } 

  const checkbox = document.querySelector("#checkbox");
  const box = document.querySelectorAll(".checkbox");
  checkbox.addEventListener("click", function () {
    for (let i = 0; i < box.length; i++) {
      box[i].checked = checkbox.checked;
      toHiddenMoney(box[i]);
    }
  });

let goodCount = document.querySelectorAll(".count");
  goodCount.forEach((item) => {
    item.addEventListener("click", function (e) {
      let target = e.target;
      if (target.className == "decrease") {
        const inp = target.nextElementSibling;
        const hidden =
          target.parentNode.parentNode.parentNode.parentNode
            .previousElementSibling;
        const checkBox =
          target.parentNode.parentNode.parentNode.parentNode
            .previousElementSibling.previousElementSibling;
        const singleVal =
          +target.parentNode.previousElementSibling.querySelector(
            ".singlePrice"
          ).innerHTML;
        if (inp.value == 1) {
          return alert("不能再减了~");
        } else {
          inp.value--;
          hidden.value = singleVal * inp.value;
          toHiddenMoney(checkBox);
        }
      }
      if (target.className == "increase") {
        const inp = target.previousElementSibling;
        const hidden =
          target.parentNode.parentNode.parentNode.parentNode
            .previousElementSibling;
        const checkBox =
          target.parentNode.parentNode.parentNode.parentNode
            .previousElementSibling.previousElementSibling;
        const singleVal =
          +target.parentNode.previousElementSibling.querySelector(
            ".singlePrice"
          ).innerHTML;
        inp.value++;
        hidden.value = singleVal * inp.value;
        toHiddenMoney(checkBox);
      }
    });
  });

  const checkboxEl = document.querySelectorAll(".checkbox");

  const edit = document.querySelector(".edit");
  let flag = true;
  const editHtml = edit.innerHTML;
  const account = document.querySelector(".account");
  const cancel = document.querySelector(".cancel");
  let newCheckbox = [];
  edit.addEventListener("click", function () {
    let editHtml2 = `<span style="color: red; font-size: 3.7333vw">完成</span>`;
    console.log(flag);
    if (flag) {
      this.innerHTML = editHtml2;
      account.style.display = "none";
      cancel.style.display = "block";
    } else {
      this.innerHTML = editHtml;
      account.style.display = "block";
      cancel.style.display = "none";
    }
    flag = !flag;
  });

  let goodsIdArr = [];
  cancel.addEventListener("click", function () {
    //获取被选中的复选框
    newCheckbox = [...checkboxEl].filter((item) => item.checked == true);
    newCheckbox.forEach((item) => {
      item.parentNode.remove();
      goodsIdArr.push(item.parentNode.dataset.id);
    });
    edit.innerHTML = editHtml;
    account.style.display = "block";
    cancel.style.display = "none";
    document.querySelector(".totalPrice").innerHTML = +0.0;
  });

function getTotalMoney() {
  let checkboxNew = document.querySelectorAll(".checkbox");
  arr = [];
  for (let i = 0; i < checkboxNew.length; i++) {
    if (checkboxNew[i].checked == true) {
      arr.push(+checkboxNew[i].nextElementSibling.value);
      getTotalPrice(arr);
    } else {
      getTotalPrice(arr);
    }
  }
}

function getTotalPrice(arr) {
  document.querySelector(".totalPrice").innerHTML = arr
    .reduce((prev, cur) => prev + cur, 0)
    .toFixed(2);
}