JS 倒计时 天/时/分/秒 计算

      let [tTime, cTime] = [new Date(targetTime.replace(/-/g, '/')).getTime(), new Date().getTime()]
      let diff = parseInt((tTime - cTime) / 1000)
      let [d, h, m, s] = [0, 0, 0, 0]
      if (diff > 0) {
        [d, h, m, s] = [
          Math.floor(diff / (3600 * 24)),
          Math.floor((diff / 3600) % 24),
          Math.floor((diff / 60) % 60),
          Math.floor(diff % 60)
        ]