JS 日期格式化方法集

/**
 * 毫秒转换友好的显示格式
 * 输出格式：21小时前
 */
function formatTime(date) {
    //获取js 时间戳 
    var time = new Date().getTime();
    //去掉 js 时间戳后三位，与php 时间戳保持一致 
    time = parseInt((time - date * 1000) / 1000);
    //存储转换值
    var s;
    if (time < 60 * 10) {
        //十分钟内 return '刚刚'; } 
    } else if ((time < 60 * 60) && (time >= 60 * 10)) {
        //超过十分钟少于1小时
        return Math.floor(time / 60) + '分钟前';
    } else if ((time < 60 * 60 * 24) && (time >= 60 * 60)) {
        //超过1小时少于24小时 
        return Math.floor(time / 60 / 60) + '小时前';
    } else if ((time < 60 * 60 * 24 * 3) && (time >= 60 * 60 * 24)) {
        //超过1天少于3天内 
        return Math.floor(time / 60 / 60 / 24) + '天前';
    } else {
        //超过3天 
        var date = new Date(parseInt(date) * 1000);
        return date.getFullYear() + "/" + (date.getMonth() + 1) + "/" + date.getDate();
    }
}

/**
 * 毫秒转换友好的显示格式
 * @param time 
 */
function formatDate(time) {
    var ago, curTime, diff, int;
    time -= 0;
    if (("" + time).length === 10) time *= 1000;
    int = parseInt;
    curTime = +new Date();
    diff = curTime - time;
    ago = "";
    if (1000 * 60 > diff) {
        ago = "刚刚";
    } else if (1000 * 60 <= diff && 1000 * 60 * 60 > diff) {
        ago = int(diff / (1000 * 60)) + "分钟前";
    } else if (1000 * 60 * 60 <= diff && 1000 * 60 * 60 * 24 > diff) {
        ago = int(diff / (1000 * 60 * 60)) + "小时前";
    } else if (1000 * 60 * 60 * 24 <= diff && 1000 * 60 * 60 * 24 * 30 > diff) {
        ago = int(diff / (1000 * 60 * 60 * 24)) + "天前";
    } else if (1000 * 60 * 60 * 24 * 30 <= diff && 1000 * 60 * 60 * 24 * 30 * 12 > diff) {
        ago = int(diff / (1000 * 60 * 60 * 24 * 30)) + "月前";
    } else {
        ago = int(diff / (1000 * 60 * 60 * 24 * 30 * 12)) + "年前";
    }
    return ago;
}

/**
 * 获取昨日时间
 */
function yesterday() {
    var timenow = new Date();
    timenow.setDate(timenow.getDate() - 1);
    //设置天数 -1 天，昨天的日期 
    var y = timenow.getFullYear();
    //年 var m = timenow.getMonth() + 1;
    //月 
    m = m < 10 ? '0' + m : m;
    var d = timenow.getDate();
    //日 
    d = d < 10 ? ('0' + d) : d;
    var yesterdayTime = y + '/' + m + '/' + d;
    //yyyy/mm/dd格式 
    return yesterdayTime;
}


/**
 * 获取近几天的日期 2018-05-09 
 * @param day 0表示当前 ，-3表示前3天， 5表示当前加5天
 */
function getDay(day) {
    var today = new Date();
    // 转毫秒
    var targetday_milliseconds = today.getTime() + 1000 * 60 * 60 * 24 * day;
    // 重新生成新时间
    today.setTime(targetday_milliseconds);
    // 年月日    
    var tYear = today.getFullYear();
    var tMonth = today.getMonth();
    var tDate = today.getDate();
    tMonth = doHandleMonth(tMonth + 1);
    tDate = doHandleMonth(tDate);
    return tYear + "-" + tMonth + "-" + tDate;
}

/**
* 获取某月有多少天
*/
function getMonthOfDay (time) {
    var date = new Date(time)
    var year = date.getFullYear()
    var mouth = date.getMonth() + 1
    var days

    //当月份为二月时，根据闰年还是非闰年判断天数
    if (mouth == 2) {
        days = (year%4==0 && year%100==0 && year%400==0) || (year%4==0 && year%100!=0) ? 28 : 29
    } else if (mouth == 1 || mouth == 3 || mouth == 5 || mouth == 7 || mouth == 8 || mouth == 10 || mouth == 12) {
        //月份为：1,3,5,7,8,10,12 时，为大月.则天数为31；
        days = 31
    } else {
        //其他月份，天数为：30.
        days = 30
    }
    return days
}

/**
* 获取某年有多少天
*/
function getYearOfDay (time) {
    var firstDayYear = this.getFirstDayOfYear(time);
    var lastDayYear = this.getLastDayOfYear(time);
    var numSecond = (new Date(lastDayYear).getTime() - new Date(firstDayYear).getTime())/1000;
    return Math.ceil(numSecond/(24*3600));
}

/**
* 获取某年的第一天
*/
function getFirstDayOfYear (time) {
    var year = new Date(time).getFullYear();
    return year + "-01-01 00:00:00";
}

/**
* 获取某年最后一天
*/
function getLastDayOfYear (time) {
    var year = new Date(time).getFullYear();
    var dateString = year + "-12-01 00:00:00";
    var endDay = this.getMonthOfDay(dateString);
    return year + "-12-" + endDay + " 23:59:59";
}

/**
* 获取某个日期是当年中的第几天
*/
function getDayOfYear (time) {
    var firstDayYear = this.getFirstDayOfYear(time);
    var numSecond = (new Date(time).getTime() - new Date(firstDayYear).getTime())/1000;
    return Math.ceil(numSecond/(24*3600));
}

/**
* 获取某个日期在这一年的第几周、
*/
function getDayOfYearWeek (time) {
    var numdays = this.getDayOfYear(time);
    return Math.ceil(numdays / 7);
}