我的：

class CountInfo {
            constructor() {
                let tfoot = document.getElementsByTagName("tfoot")[0]
                let countInfoTag = tfoot.children[0].children[1]
                let tmp = countInfoTag.innerHTML.match(/\d+/g)
                let countInfo = {
                    price: 0,
                    num: 0
                }
                countInfo.price = (tmp[0] - 0) + (tmp[1] - 0) * 0.01
                countInfo.num = tmp[2] - 0
                this.countInfoTag = countInfoTag
                this.countInfo = countInfo
            }

            delete(price) {
                this.countInfo.num--
                this.countInfo.price = this.countInfo.price - price
                this.countInfoTag.innerHTML = `${this.countInfo.price.toFixed(2)}(${this.countInfo.num}件商品)`
            }

            add(price) {
                this.countInfo.num++
                this.countInfo.price = this.countInfo.price + price
                this.countInfoTag.innerHTML = `${this.countInfo.price.toFixed(2)}(${this.countInfo.num}件商品)`
            }
        }
        bind()

        function add(items) {
            let tr = document.createElement("tr")
            tr.innerHTML = `<td>${items.name}</td><td>${items.price.toFixed(2)}</td><td><a href="javascript:void(0);">删除</a></td>`
            let tbody = document.getElementsByTagName("tbody")[0]
            tbody.appendChild(tr)
            tr.children[2].children[0].onclick = click
            const countInfo = new CountInfo()
            countInfo.add(items.price)
        }

        function bind() {
            let tags = document.getElementsByTagName("a")
            const LEN = tags.length
            for (let i = 0; i < LEN; i++) {
                tags[i].onclick = click
            }
        }

        function click(e) {
            const countInfo = new CountInfo()

            let tr = e.srcElement.parentElement.parentElement
            countInfo.delete(tr.children[1].innerHTML - 0)
            tr.remove()
        }