function add(items) {
  let tbody = jsTrolley.querySelector('tbody')
  items.forEach(item => tbody.insertAdjacentHTML('beforeend', `<tr><td>${item.name}</td><td>${item.price.toFixed(2)}</td><td><a href="javascript:void(0);">删除</a></td></tr>`))
  calCount()
}

function bind() {
  let tbody = jsTrolley.querySelector('tbody')

  tbody.onclick = function (event) {
	let target = event.target

	if (target.tagName != 'A') return

	target.closest('tr').remove()

	calCount()
  }
}

function calCount() {
  let tbody = jsTrolley.querySelector('tbody')

  let count = [].reduce.call(tbody.rows, (count, tr) => {
  let priceTd = tr.children[1]
  return count + parseFloat(priceTd.innerHTML)
  }, 0)

  jsTrolley.querySelector('tfoot').querySelector('td').innerHTML = `${count.toFixed(2)}(${tbody.rows.length}件商品)`
};

不能用for of遍历dom对象tbody.rows,会失败,我也不知道为什么