js获取今年第几周和获取周的开始和结束日期

获取今年第几周

// 页面初始时获取当前是本年第几周function getYearWeek(a, b, c) {//a为年 b为月 c为日/* date1是当前日期 date2是当年第一天 d是当前日期是今年第多少天 用d + 当前年的第一天的周差距的和在除以7就是本年第几周 */var date1 = new Date(a, parseInt(b) - 1, c),date2 = new Date(a, 0, 1),d = Math.round((date1.valueOf() - date2.valueOf()) / 86400000);return Math.ceil((d + (date2.getDay() + 1 - 1)) / 7);}// 页面初始需要的周和月的数据const date = new Date();// 获取当前第几周let week =date.getFullYear() +"-" +getYearWeek(date.getFullYear(),Number(date.getMonth()) + 1,date.getDate());//获取周的开始结束日期let wStartEnd = week_date(week);

周的开始和结束日期

// 第n年的第n周，获取开始和结束时间 （星期一为一周的开始）function week_date(weekstr) {let year = weekstr.split("-")[0];let weekNo = weekstr.split("-")[1];// 此年1号是星期几// console.log('调用时传的',year,weekNo);let oneday = new Date(year + "-01-01").getDay(); //0-6// console.log(oneday);// 方便计算，当为星期天时为7if (oneday == 0) {oneday = 7;}let one_fistday;let one_lastday;// 如果1号刚好是星期一if (oneday == 1) {one_fistday = year + "-01-01";one_lastday = year + "-01-07";} else {let jj = 8 - oneday;one_fistday =year -1 +"-12-" +(31 - oneday + 2 > 9 ? 31 - oneday + 2 : "0" + (31 - oneday + 2));one_lastday = year + "-01-" + (jj > 9 ? jj : "0" + jj);}let fistday;let lastday;// 如果刚好是第一周if (weekNo == 1) {fistday = one_fistday;lastday = one_lastday;} else {fistday = addDate(one_lastday, (weekNo - 2) * 7 + 1);lastday = addDate(one_lastday, (weekNo - 1) * 7);}console.log(fistday, lastday);return [fistday, lastday];}//日期加减法 date参数为计算开始的日期，days为需要加的天数//格式:addDate('-1-11',20)function addDate(date, days) {var d = new Date(date);d.setDate(d.getDate() + days);var m = d.getMonth() + 1;return (d.getFullYear() +"-" +(m > 9 ? m : "0" + m) +"-" +(d.getDate() > 9 ? d.getDate() : "0" + d.getDate()));}console.log("查看", week_date("-11"));

获取周开始结束也是在其他博主那里看到的，是好久之前的了如有知道请帮忙加个连接，谢谢！