计算两个时间相差多少

 // 计算两个时间差 dateBegin 开始时间
    timeFn(dateEnd) {
      var dateBegin = Date.parse(new Date()); //获取当前时间
      var dateDiff =
        dateBegin - Date.parse(new Date(dateEnd.replace(/-/g, "/"))); //时间差的毫秒数
      var dayDiff = Math.floor(dateDiff / (24 * 3600 * 1000)); //计算出相差天数
      var leave1 = dateDiff % (24 * 3600 * 1000); //计算天数后剩余的毫秒数
      var hours = Math.floor(leave1 / (3600 * 1000)); //计算出小时数
      //计算相差分钟数
      var leave2 = leave1 % (3600 * 1000); //计算小时数后剩余的毫秒数
      var minutes = Math.floor(leave2 / (60 * 1000)); //计算相差分钟数
      //计算相差秒数
      var leave3 = leave2 % (60 * 1000); //计算分钟数后剩余的毫秒数
      var seconds = Math.round(leave3 / 1000);
      var leave4 = leave3 % (60 * 1000); //计算分钟数后剩余的毫秒数
      var minseconds = Math.round(leave4 / 1000);
      var timeFn =
        "耗时：" +
        dayDiff +
        "天 " +
        hours +
        "小时 " +
        minutes +
        " 分钟" +
        seconds +
        " 秒" +
        minseconds +
        "毫秒";
      return dayDiff;
    },