封装一些JavaScript时间相关的方法，精确到微秒

每次网上搜太浪费时间了，一次性整理齐，其他时间段可以推导代码写法。

var now = new Date(); //当前日期
var nowDayOfWeek = now.getDay() - 1; //今天本周的第几天
var nowDay = now.getDate(); //当前日
var nowMonth = now.getMonth(); //当前月
var nowYear = now.getYear(); //当前年
nowYear += (nowYear < 2000) ? 1900 : 0;
var lastMonthDate = new Date(); //上月日期
lastMonthDate.setDate(1);
lastMonthDate.setMonth(lastMonthDate.getMonth() - 1);
var lastYear = lastMonthDate.getYear();
var lastMonth = lastMonthDate.getMonth();

//格式化时间：yyyy-MM-dd hh:mm:ss
function formatDate(date) {
    var myyear = date.getFullYear();
    var mymonth = date.getMonth() + 1;
    var myweekday = date.getDate();
    var myhours = date.getHours();
    var myminutes = date.getMinutes();
    var myseconds = date.getSeconds();
    if (mymonth < 10) {
        mymonth = "0" + mymonth;
    }
    if (myweekday < 10) {
        myweekday = "0" + myweekday;
    }
    return (myyear + "-" + mymonth + "-" + myweekday + " " + myhours + ":" + myminutes + ":" + myseconds);
}


//获得某月的天数
function getMonthDays(myMonth) {
    var monthStartDate = new Date(nowYear, myMonth, 1);
    var monthEndDate = new Date(nowYear, myMonth + 1, 1);
    var days = (monthEndDate - monthStartDate) / (1000 * 60 * 60 * 24);
    return days;
}

//获得本季度的开始月份
function getQuarterStartMonth() {
    var quarterStartMonth = 0;
    if (nowMonth < 3) {
        quarterStartMonth = 0;
    }
    if (2 < nowMonth && nowMonth < 6) {
        quarterStartMonth = 3;
    }
    if (5 < nowMonth && nowMonth < 9) {
        quarterStartMonth = 6;
    }
    if (nowMonth > 8) {
        quarterStartMonth = 9;
    }
    return quarterStartMonth;
}


//获得本周的开始时间
function getWeekStartDate() {
    var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);
    return formatDate(weekStartDate);
}

//获得本周的结束时间
function getWeekEndDate() {
    var weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek), 23, 59, 59, 999);
    return formatDate(weekEndDate);
}

//获得上周的开始时间
function getLastWeekStartDate() {
    var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 7);
    return formatDate(weekStartDate);
}

//获得上周的结束时间
function getLastWeekEndDate() {
    var weekEndDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 1, 23, 59, 59, 999);
    return formatDate(weekEndDate);
}

//获得本月的开始时间
function getMonthStartDate() {
    var monthStartDate = new Date(nowYear, nowMonth, 1);
    return formatDate(monthStartDate);
}

//获得本月的结束时间
function getMonthEndDate() {
    var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth), 23, 59, 59, 999);
    return formatDate(monthEndDate);
}

//获得上月开始时间
function getLastMonthStartDate() {
    if (lastMonth == 11) {
        var lastMonthStartDate = new Date(nowYear - 1, lastMonth, 1);
    } else {
        var lastMonthStartDate = new Date(nowYear, lastMonth, 1);
    }
    return formatDate(lastMonthStartDate);
}

//获得上月结束时间
function getLastMonthEndDate() {
    if (lastMonth == 11) {
        var lastMonthEndDate = new Date(nowYear - 1, lastMonth, getMonthDays(lastMonth), 23, 59, 59, 999);
    } else {
        var lastMonthEndDate = new Date(nowYear, lastMonth, getMonthDays(lastMonth), 23, 59, 59, 999);
    }
    return formatDate(lastMonthEndDate);
}

//获得本季度的开始时间
function getQuarterStartDate() {
    var quarterStartDate = new Date(nowYear, getQuarterStartMonth(), 1);
    return formatDate(quarterStartDate);
}

//获得本季度的结束时间
function getQuarterEndDate() {
    var quarterEndMonth = getQuarterStartMonth() + 2;
    var quarterStartDate = new Date(nowYear, quarterEndMonth,
        getMonthDays(quarterEndMonth), 23, 59, 59);
    return formatDate(quarterStartDate);
}

//获得昨天的开始时间
function getYesterdayStartTime() {
    var yesterdayStartDate = new Date(nowYear, nowMonth, nowDay - 1, 0, 0, 0);
    return formatDate(yesterdayStartDate);
}

//获得昨天的结束时间
function getYesterdayEndTime() {
    var yesterdayEndDate = new Date(nowYear, nowMonth, nowDay - 1, 23, 59, 59, 999);
    return formatDate(yesterdayEndDate);
}

//获得过去7天的开始时间
function get7AgoStartTime() {
    var sevenDayStartDate = new Date(nowYear, nowMonth, nowDay - 7);
    return formatDate(sevenDayStartDate)
}

//获得过去7天的结束时间
function get7AgoEndTime() {
    var sevenDayStartDate = new Date(nowYear, nowMonth, nowDay - 1, 23, 59, 59, 999);
    return formatDate(sevenDayStartDate)
}

//获得过去30天的开始时间
function get30AgoStartTime() {
    var sevenDayStartDate = new Date(nowYear, nowMonth, nowDay - 30);
    return formatDate(sevenDayStartDate)
}

//获得过去7天的结束时间
function get30AgoEndTime() {
    var sevenDayEndDate = new Date(nowYear, nowMonth, nowDay - 1, 23, 59, 59, 999);
    return formatDate(sevenDayEndDate)
}

console.log('获得本周的开始时间:' + getWeekStartDate())
console.log('获得本周的结束时间:' + getWeekEndDate())
console.log('获得上周的开始时间:' + getLastWeekStartDate())
console.log('获得上周的结束时间:' + getLastWeekEndDate())
console.log('获得本月的开始时间:' + getMonthStartDate())
console.log('获得本月的结束时间:' + getMonthEndDate())
console.log('获得上月开始时间:' + getLastMonthStartDate())
console.log('获得上月结束时间:' + getLastMonthEndDate())
console.log('获得本季度的开始时间:' + getQuarterStartDate())
console.log('获得本季度的结束时间:' + getQuarterEndDate())
console.log('获得昨天的开始时间:' + getYesterdayStartTime())
console.log('获得昨天的结束时间:' + getYesterdayEndTime())
console.log('获得过去7天的开始时间:' + get7AgoStartTime())
console.log('获得过去7天的结束时间:' + get7AgoEndTime())
console.log('获得过去30天的开始时间:' + get30AgoStartTime())
console.log('获得过去30天的结束时间:' + get30AgoEndTime())