js jquery 取得周月年时间

function 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);
}
var now = new Date(); //当前日期
var nowDayOfWeek = now.getDay(); //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();

//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;
}
//获得本周的开始日期
function getWeekStartDate() {
var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);
return formatDate(weekStartDate);
}
//获得本周的结束日期
function getWeekEndDate() {
var weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek));
return formatDate(weekEndDate);
}
//获得上周的开始日期
function getLastWeekStartDate() {
var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 7);
return formatDate(weekStartDate);
}
//获得上周的结束日期
function getLastWeekEndDate() {
debugger;
var weekEndDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek - 1);
return formatDate(weekEndDate);
}
//获得本月的开始日期
function getMonthStartDate() {
var monthStartDate = new Date(nowYear, nowMonth, 1);
return formatDate(monthStartDate);
}
//获得本月的结束日期
function getMonthEndDate() {
var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth));
return formatDate(monthEndDate);
}
//获得上月开始时间
function getLastMonthStartDate() {
var years = lastMonth == 11 ? (nowYear - 1) : nowYear;
var lastMonthStartDate = new Date(years, lastMonth, 1);
return formatDate(lastMonthStartDate);
}
//获得上月结束时间
function getLastMonthEndDate() {
var years = lastMonth == 11 ? (nowYear - 1) : nowYear;
var lastMonthEndDate = new Date(years, lastMonth, getMonthDays(lastMonth));
return formatDate(lastMonthEndDate);
}