题解 | #购物面板#

zjtaiduola.onclick = reduceNum
zjtaishaola.onclick = addNum
kltaiduola.onclick = reduceNum
kltaishaola.onclick = addNum

function reduceNum(event) {
  let span = event.target.parentNode.nextElementSibling.firstChild

  if (span.innerHTML == 0) return

  span.innerHTML = +span.innerHTML - 1

  count()
}

function addNum(event) {
  let span = event.target.parentNode.previousElementSibling.firstChild
  span.innerHTML = +span.innerHTML + 1

  count()
}

function count() {
  let chicken = parseInt(klsl.closest('tr').children[1].innerHTML) * klsl.innerHTML
  let coke = parseInt(zjsl.closest('tr').children[1].innerHTML) * zjsl.innerHTML
  total.innerHTML = chicken + coke
}