通过出生日期和当前日期计算年，月，天(我的年龄、在职日期)

常见应用：

我多大了，在职时间

C#代码：

    /// 通过出生日期和当前日期计算年，月，天
    /// </summary>
    /// <param name="birth">出生日期</param>
    /// <param name="now">当前日期</param>
    /// <param name="year">年</param>
    /// <param name="month">月</param>
    /// <param name="day">天</param>
    private void GetDateByBirth(DateTime birth, DateTime now, out int year, out int month,
    out int day)
    {
        //出生日期的年，月，日
        int birthYear = birth.Year;
        int birthMonth = birth.Month;
        int birthDay = birth.Day;

        //当前时间的年,月,日
        int nowYear = now.Year;
        int nowMonth = now.Month;
        int nowDay = now.Day;

        //得到天
        if (nowDay >= birthDay)
        {
            day = nowDay - birthDay;
        }
        else
        {
            nowMonth -= 1;
            day = GetDay(nowMonth, nowYear) + nowDay - birthDay;
        }

        //得到月
        if (nowMonth >= birthMonth)
        {
            month = nowMonth - birthMonth;
        }
        else
        {
            nowYear -= 1;
            month = 12 + nowMonth - birthMonth;
        }

        //得到年
        year = nowYear - birthYear;
    }

    /// <summary>
    /// 获取天数
    /// </summary>
    private int GetDay(int month, int year)
    {
        int day = 0;
        switch (month)
        {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                day = 31;
                break;
            case 2:
                //闰年天，平年天
                if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
                {
                    day = 29;
                }
                else
                {
                    day = 28;
                }
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                day = 30;
                break;
        }
        return day;
    }

 Js代码：

function GetDateValue(entry){
            //差值
            var year;
            var month;
            var day;

            //入职日期
            var dateArr = entry.split("-");
            var entry_year = parseInt(dateArr[0]);
            var entry_month = parseInt(dateArr[1]);
            var entry_day = parseInt(dateArr[2]);
            //当前日期
            var d = new Date();
            var now_year = d.getFullYear();
            var now_day = d.getDate();
            var now_month = d.getMonth() + 1;

            //得到天
            if(now_day >= entry_day){
                day = now_day - entry_day;
            }else{
                now_month = now_month - 1;
                day = GetDay(now_month,now_year) + now_day - entry_day;
            }
            //得到月
            if(now_month >= entry_month){
                month = now_month - entry_month;
            }else{
                now_year = now_year -1;
                month = 12 + now_month - entry_month;
            }
            //得到年
            year = now_year - entry_year;

            //字符串
            var basic_experience = " 在职";
            if (year != 0)
                basic_experience += Math.abs(year) + "年";
            if (month != 0)
                basic_experience += Math.abs(month) + "月";
            if (day != 0)
                basic_experience += Math.abs(day) + "天";
            return basic_experience;
        }
        //获取天
        function GetDay(month,year){
            var day = 0;
            if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12){
                day = 31;
            }else if(month == 2){
                if(year % 4 == 0 && year % 100 !=0 || year % 400 == 0){ 
                    day = 29;
                }else{
                    day = 28;
                }
            }else if(month == 4 || month == 6 || month == 9 || month == 11){
                day = 30;
            }
            return day;
        }