前端超实用用的js倒计时功能,及各种处理时间功能_前端算倒计时怎么除

1.js倒计时功能  

 calcTime(str,seeTime) {
    let date1 = new Date(str);  //开始时间
    let date2 = new Date();  //结束时间
    let date3 = date2.getTime() - date1.getTime()  //时间差的毫秒数
    let isFirst = (seeTime - date2.getTime() > 0) ? true:false;
    let isOvertime = false;
 
    //计算出相差天数
    let days = Math.floor(date3 / (24 * 3600 * 1000))
    //计算出小时数
    let leave1 = date3 % (24 * 3600 * 1000)    //计算天数后剩余的毫秒数
    let hours = Math.floor(leave1 / (3600 * 1000))
    //计算相差分钟数
    let leave2 = leave1 % (3600 * 1000)        //计算小时数后剩余的毫秒数
    let minutes = Math.floor(leave2 / (60 * 1000))
    //计算相差秒数
    let leave3 = leave2 % (60 * 1000)      //计算分钟数后剩余的毫秒数
    let seconds = Math.round(leave3 / 1000);
 
    if (hours <= 0) {
      hours = 0;
    } else {
      isOvertime = true;
    }
    if (minutes <= 0) {
      minutes = '00';
    } else if (minutes > 3) {
      isOvertime = true;
    }
    if (minutes.toString().length == 1) {
      minutes = '0' + minutes;
    }
    if (seconds < 0) {
      seconds = '00';
    }
    if (seconds.toString().length == 1) {
      seconds = '0' + seconds;
    }
    return [hours + ":" + minutes + ":" + seconds, isOvertime,isFirst];
  },

2.处理时间戳转化为各种想要的格式日期

function time(time, type) {
  var datetime = new Date();
  datetime.setTime(time);
  var year = datetime.getFullYear();
  var month = datetime.getMonth() + 1 < 10 ? "0" + (datetime.getMonth() + 1) : datetime.getMonth() + 1;
  var date = datetime.getDate() < 10 ? "0" + datetime.getDate() : datetime.getDate();
  var hour = datetime.getHours() < 10 ? "0" + datetime.getHours() : datetime.getHours();
  var minute = datetime.getMinutes() < 10 ? "0" + datetime.getMinutes() : datetime.getMinutes();
  var second = datetime.getSeconds() < 10 ? "0" + datetime.getSeconds() : datetime.getSeconds();
  if (type == '1') {
      return year + "." + month + "-" + date + "日";
  }
  if (type == '2') {
      return year + "-" + month + "-" + date;
  }
  if (type == '3') {
      return month + "-" + date;
  }
  if(type == '4'){
      return month;
  }
  if(type == '5'){
      return date;
  }
  if(type == '6'){
      return year + "." + month + "." + date + " " + hour + ":" + minute + ":" + second;
  }
  if(type == '7'){
      return year + "-" + month + "-" + date + " " + hour + ":" + minute + ":" + second;
  }
  if(type == '8'){
      return year + "-" + month + "-" + date + " " + hour + ":" + minute;
  }
  if(type == '9'){
      return month + "-" + date + " " + hour + ":" + minute;
  }
  if(type == '10'){
    return  hour + ":" + minute
}
}

3.获取当前时间日期

function getNowTime() {
  var now = new Date();
  var year = now.getFullYear();
  var month = now.getMonth() + 1;
  var day = now.getDate();
  if (month < 10) {
    month = '0' + month;
  };
  if (day < 10) {
    day = '0' + day;
  };
  //  如果需要时分秒，就放开
  // var h = now.getHours();
  // var m = now.getMinutes();
  // var s = now.getSeconds();
  var formatDate = year + '-' + month + '-' + day;
  return formatDate;
}

4.获取前一天的日期

function getDay(num, str) {
  var today = new Date();
  var nowTime = today.getTime();
  var ms = 24*3600*1000*num;
  today.setTime(parseInt(nowTime + ms));
  var oYear = today.getFullYear();
  var oMoth = (today.getMonth() + 1).toString();
  if (oMoth.length <= 1) oMoth = '0' + oMoth;
  var oDay = today.getDate().toString();
  if (oDay.length <= 1) oDay = '0' + oDay;
  return oYear + str + oMoth + str + oDay;
}