js 獲取 本周、上周、本月、上月、本季度、上季度的開始結束日期

/** * 獲取本周、本季度、本月、上月的開始日期、結束日期 */var now = new Date(); //當前日期var nowDayOfWeek = now.getDay(); //今天本周的第幾天var nowDay = now.getDate(); //當前日var nowMonth = now.getMonth(); //當前月var nowYear = now.getYear(); //當前年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();//格式化日期：yyyy-MM-ddfunction formatDate(date) {  var myyear = date.getFullYear();  var mymonth = date.getMonth() + 1;  var myweekday = date.getDate();  if (mymonth < 10) {    mymonth = "0" + mymonth;  }  if (myweekday < 10) {    myweekday = "0" + myweekday;  }  return (myyear + "-" + mymonth + "-" + myweekday);}//獲得某月的天數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;}//獲得本季度的開始月份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;}//獲得本周的開始日期function getWeekStartDate() {  var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);  return formatDate(weekStartDate);}//獲得本周的結束日期function getWeekEndDate() {  var weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek));  return formatDate(weekEndDate);}//獲得上周的開始日期function getLastWeekStartDate() {  var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 7);  return formatDate(weekStartDate);}//獲得上周的結束日期function getLastWeekEndDate() {  var weekEndDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 1);  return formatDate(weekEndDate);}//獲得本月的開始日期function getMonthStartDate() {  var monthStartDate = new Date(nowYear, nowMonth, 1);  return formatDate(monthStartDate);}//獲得本月的結束日期function getMonthEndDate() {  var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth));  return formatDate(monthEndDate);}//獲得上月開始時間function getLastMonthStartDate() {  var lastMonthStartDate = new Date(nowYear, lastMonth, 1);  return formatDate(lastMonthStartDate);}//獲得上月結束時間function getLastMonthEndDate() {  var lastMonthEndDate = new Date(nowYear, lastMonth, getMonthDays(lastMonth));  return formatDate(lastMonthEndDate);}//獲得本季度的開始日期function getQuarterStartDate() {  var quarterStartDate = new Date(nowYear, getQuarterStartMonth(), 1);  return formatDate(quarterStartDate);}//或的本季度的結束日期function getQuarterEndDate() {  var quarterEndMonth = getQuarterStartMonth() + 2;  var quarterStartDate = new Date(nowYear, quarterEndMonth,      getMonthDays(quarterEndMonth));  return formatDate(quarterStartDate);}