JS计算指定日期是距今的第几周，星期几
2020-07-07 本文已影响0人
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<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
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<body>
<input id="RFLOT_DATE" type="date"/>
<input id="RFLOT_LOT" />
<script>
/**
* 判断年份是否为润年
*
* @param {Number} year
*/
function isLeapYear(year) {
return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
/**
* 获取某一年份的某一月份的天数
*
* @param {Number} year
* @param {Number} month
*/
function getMonthDays(year, month) {
return [31, null, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month] || (isLeapYear(year) ? 29 : 28);
}
/**
* 获取某年的某天是第几周
* @param {Number} y
* @param {Number} m
* @param {Number} d
* @returns {Number}
*/
function getWeekNumber(y, m, d) {
var now = new Date(y, m - 1, d),
year = now.getFullYear(),
month = now.getMonth(),
days = now.getDate();
//那一天是那一年中的第多少天
for (var i = 0; i < month; i++) {
days += getMonthDays(year, i);
}
//那一年第一天是星期几
var yearFirstDay = new Date(year, 0, 1).getDay() || 7;
var week = null;
if (yearFirstDay == 1) {
week = Math.ceil(days / yearFirstDay);
} else {
days -= (7 - yearFirstDay + 1);
week = Math.ceil(days / 7) + 1;
}
return week;
}
var lot;
function loaddate() {
var now = new Date();
var str = now.getFullYear() + "-" + ((now.getMonth() + 1) < 10 ? "0" : "") + (now.getMonth() + 1) + "-" + (now.getDate() < 10 ? "0" : "") + now.getDate();
var year = now.getFullYear();
var month = ((now.getMonth() + 1) < 10 ? "0" : "") + (now.getMonth() + 1);
var date = (now.getDate() < 10 ? "0" : "") + now.getDate();
document.getElementById("RFLOT_DATE").value = str;
var ttwo = year.toString().substring(2, year.length);
lot = ttwo + month + date;
console.log(year,month,date,ttwo)
console.log(getWeekNumber(year,month,date),ttwo)
document.getElementById("RFLOT_LOT").value=getWeekNumber(year,month,date)+ttwo;
}
loaddate()
</script>
<script>
(function(){
/*
* 说明：
* 一周的起始计算方式不同国家有所不同，很多其他国家将周日作为一周的开始
* 本代码使用中国习惯，将周一作为每周的开始
* 特此说明
*/
function TodayInfo(start) {
var WEEKLEN = 7, // 一周7天为常量
WEEKDAYS = ["日", "一", "二", "三", "四", "五", "六"],
weekInfo = {"week": null, "day": null}, // 初始化返回信息，默认第null周，星期null
oneDay = 24 * 60 * 60 * 1000, // 一天的毫秒时长
weekLeave, // 开学当天所在周剩余天数
weekStart, // 开学当天start是星期几
today, // 今天
dateDiff, // 今天与开学当天日期差
sDate; //开学之日，日期对象
var rDateStr = /\d{4}[\/-]\d{1,2}[\/-]\d{1,2}/g; // 简单的日期格式校验：2013/12/19
if (!rDateStr.test(start)) {
alert("请使用合法的开学日期！！！");
return weekInfo;
}
sDate = new Date(start.replace("-", "/"));
weekStart = sDate.getDay();
weekStart = weekStart === 0 ? 7 : weekStart; // JS中周日的索引为0，这里转换为7，方便计算
weekLeave = WEEKLEN - weekStart;
today = new Date();
weekInfo.day = WEEKDAYS[today.getDay()];
today = new Date(today.getFullYear() + "/" + (today.getMonth() + 1) + "/" + today.getDate());
dateDiff = today - sDate;
if (dateDiff < 0) {
alert("别开玩笑了，你还没开学呢！！！");
return weekInfo;
}
dateDiff = parseInt(dateDiff / oneDay);
weekInfo.week = Math.ceil((dateDiff - weekLeave) / WEEKLEN) + 1;
return weekInfo;
}
// 测试结果
var td = TodayInfo("2020/1/1");
console.log("今天是自2013/12/16日，开学以来的第 " + td.week + " 周，今天星期" + td.day);
td = TodayInfo("2013/11/11");
console.log("今天是自2013/11/11日，开学以来的第 " + td.week + " 周，今天星期" + td.day);
td = TodayInfo("2013/09/01");
console.log("今天是自2013/09/01日，开学以来的第 " + td.week + " 周，今天星期" + td.day);
td = TodayInfo("2013/12/29");
console.log("今天是自2013/12/29日，开学以来的第 " + td.week + " 周，今天星期" + td.day);
})();
</script>
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参考：https://www.cnblogs.com/mawuhen/p/4020757.html
https://www.cnblogs.com/yangpeng-jingjing/p/7527635.html
