js得到今天日期、本周、本月、本季度、本年起始和结束日期

js得到今天日期、本周、本月、本年起始和结束日期，得到今天、昨天、明天日期。

function getDate(dates) {    var dd = new Date();    var n = dates || 0;    dd.setDate(dd.getDate() + n);    var y = dd.getFullYear();    var m = dd.getMonth() + 1;    var d = dd.getDate();    m = m < 10 ? "0" + m: m;    d = d < 10 ? "0" + d: d;    var day = y + "-" + m + "-" + d;    return day;}; getDate(dates)  //dates为数字类型，0代表今日,-1代表昨日，1代表明日，返回yyyy-mm-dd格式字符串，dates不传默认代表今日。

得到本周、上周、下周的起始、结束日期

function getMonday(type, dates) {    var now = new Date();    var nowTime = now.getTime();    var day = now.getDay();    var longTime = 24 * 60 * 60 * 1000;    var n = longTime * 7 * (dates || 0);    if (type == "s") {        var dd = nowTime - (day - 1) * longTime + n;    };    if (type == "e") {        var dd = nowTime + (7 - day) * longTime + n;    };    dd = new Date(dd);    var y = dd.getFullYear();    var m = dd.getMonth() + 1;    var d = dd.getDate();    m = m < 10 ? "0" + m: m;    d = d < 10 ? "0" + d: d;    var day = y + "-" + m + "-" + d;    return day;}; getMonday(type,dates)  //type为字符串类型，有两种选择，"s"代表开始,"e"代表结束，dates为数字类型，不传或0代表本周，-1代表上周，1代表下周getMonday("s",1)  //得到下周一的yyyy-mm-dd格式日期getMonday("e",1)  //得到下周日的yyyy-mm-dd格式日期

得到本月、上月、下月的起始、结束日期

function getMonth(type, months) {    var d = new Date();    var year = d.getFullYear();    var month = d.getMonth() + 1;    if (Math.abs(months) > 12) {        months = months % 12;    };    if (months != 0) {        if (month + months > 12) {            year++;            month = (month + months) % 12;        } else if (month + months < 1) {            year--;            month = 12 + month + months;        } else {            month = month + months;        };    };    month = month < 10 ? "0" + month: month;    var date = d.getDate();    var firstday = year + "-" + month + "-" + "01";    var lastday = "";    if (month == "01" || month == "03" || month == "05" || month == "07" || month == "08" || month == "10" || month == "12") {        lastday = year + "-" + month + "-" + 31;    } else if (month == "02") {        if ((year % 4 == 0 && year % 100 != 0) || (year % 100 == 0 && year % 400 == 0)) {            lastday = year + "-" + month + "-" + 29;        } else {            lastday = year + "-" + month + "-" + 28;        };    } else {        lastday = year + "-" + month + "-" + 30;    };    var day = "";    if (type == "s") {        day = firstday;    } else {        day = lastday;    };    return day;}; getMonth(type,months)  //type为字符串类型，有两种选择，"s"代表开始,"e"代表结束，months为数字类型，不传或0代表本月，-1代表上月，1代表下月getMonth("s",1)  //得到下月第一天的yyyy-mm-dd格式日期getMonth("e",1)  //得到下月最后一天的yyyy-mm-dd格式日期

得到今年、去年、明年的开始、结束日期

function getYear(type, dates) {    var dd = new Date();    var n = dates || 0;    var year = dd.getFullYear() + Number(n);    if (type == "s") {        var day = year + "-01-01";    };    if (type == "e") {        var day = year + "-12-31";    };    if (!type) {        var day = year + "-01-01/" + year + "-12-31";    };    return day;}; getYear(type,dates)  //type为字符串类型，有两种选择，"s"代表开始,"e"代表结束，dates为数字类型，不传或0代表今年，-1代表去年，1代表明年getYear("s",1)  //得到明年第一天的yyyy-mm-dd格式日期getYear("e",1)  //得到明年最后一天的yyyy-mm-dd格式日期

得到本季度的开始、结束日期

function getQuarterMonth(type){  var now = new Date(); var nowMonth = now.getMonth();var year = now.getFullYear();    var quarterStartMonth = 1;         if(nowMonth<3){            quarterStartMonth = 1;         }         if(2<nowMonth && nowMonth<6){            quarterStartMonth = 4;         }         if(5<nowMonth && nowMonth<9){            quarterStartMonth = 7;         }         if(nowMonth>8){            quarterStartMonth = 10;         }     if (type == "s") {        var day = year+"-"+quarterStartMonth+"-01";     };//1-3 4-6 7-9 10-12    if (type == "e") {    if(quarterStartMonth==1){    var day = year+"-"+(quarterStartMonth+2)+"-31";    }    if(quarterStartMonth==10){    var day = year+"-"+(quarterStartMonth+2)+"-31";    }    if(quarterStartMonth==4){    var day = year+"-"+(quarterStartMonth+2)+"-30";    }    if(quarterStartMonth==7){    var day = year+"-"+(quarterStartMonth+2)+"-30";    }    };    return day;     } getQuarterMonth("s",1)  //得到本季度第一天的yyyy-mm-dd格式日期getQuarterMonth("e",1)  //得到本季度最后一天的yyyy-mm-dd格式日期