像PHP中一样在JavaScript中获得一周的时间
如何获取当年的周数，如PHP的date('W') ？
它应该是ISO-8601星期数，周一从周一开始。
你应该能够得到你想要的： http : //www.merlyn.demon.co.uk/js-date6.htm#YWD 。
在同一个网站上更好的链接是： 与周工作 。
编辑
这里是一些基于所提供的链接和由Dommer公布的最早的代码。 已经在http://www.merlyn.demon.co.uk/js-date6.htm#YWD对结果进行了轻度testing。 请彻底testing，不提供保证。
编辑2017年
在观察夏令时的date和1月1日星期五的年份有一个问题。 通过使用所有的UTC方法修复。 以下内容将返回与Moment.js相同的结果。
/* For a given date, get the ISO week number * * Based on information at: * * http://www.merlyn.demon.co.uk/weekcalc.htm#WNR * * Algorithm is to find nearest thursday, it's year * is the year of the week number. Then get weeks * between that date and the first day of that year. * * Note that dates in one year can be weeks of previous * or next year, overlap is up to 3 days. * * eg 2014/12/29 is Monday in week 1 of 2015 * 2012/1/1 is Sunday in week 52 of 2011 */ function getWeekNumber(d) { // Copy date so don't modify original d = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate())); // Set to nearest Thursday: current date + 4 - current day number // Make Sunday's day number 7 d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay()||7)); // Get first day of year var yearStart = new Date(Date.UTC(d.getUTCFullYear(),0,1)); // Calculate full weeks to nearest Thursday var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7); // Return array of year and week number return [d.getUTCFullYear(), weekNo]; } var result = getWeekNumber(new Date()); document.write('It\'s currently week ' + result[1] + ' of ' + result[0]);
按照http://javascript.about.com/library/blweekyear.htm
Date.prototype.getWeek = function() { var onejan = new Date(this.getFullYear(),0,1); var millisecsInDay = 86400000; return Math.ceil((((this - onejan) /millisecsInDay) + onejan.getDay()+1)/7); };
你也可以使用momentjs库：
moment().format('W')
Jacob Wright的Date.format()库以PHP的date()函数的样式实现了date格式，并且支持ISO-8601星期编号：
new Date().format('W');
对于一个星期的数字来说，这可能有点矫枉过正，但是它确实支持PHP格式的格式，如果你要做很多事情的话，这个格式非常方便。
如上所述，但没有一个类：
let now = new Date(); let onejan = new Date(now.getFullYear(), 0, 1); week = Math.ceil( (((now - onejan) / 86400000) + onejan.getDay() + 1) / 7 );
getWeekOfYear: function(date) { var target = new Date(date.valueOf()), dayNumber = (date.getUTCDay() + 6) % 7, firstThursday; target.setUTCDate(target.getUTCDate() - dayNumber + 3); firstThursday = target.valueOf(); target.setUTCMonth(0, 1); if (target.getUTCDay() !== 4) { target.setUTCMonth(0, 1 + ((4 - target.getUTCDay()) + 7) % 7); } return Math.ceil((firstThursday - target) / (7 * 24 * 3600 * 1000)) + 1; }
以下代码与时区无关（使用UTCdate），并根据https://en.wikipedia.org/wiki/ISO_8601
我发现在Oracle的规范中描述的Java SE的SimpleDateFormat类很有用： http ： //goo.gl/7MbCh5 。 在我的Google Apps脚本中，它的工作方式如下所示：
function getWeekNumber() { var weekNum = parseInt(Utilities.formatDate(new Date(), "GMT", "w")); Logger.log(weekNum); }
例如，在电子表格macros中，您可以检索文件的实际时区：
function getWeekNumber() { var weekNum = parseInt(Utilities.formatDate(new Date(), SpreadsheetApp.getActiveSpreadsheet().getSpreadsheetTimeZone(), "w")); Logger.log(weekNum); }
这将“getWeek”方法添加到Date.prototype中，该方法返回从一年开始的周数。 参数定义了一周中哪一天考虑第一天。 如果没有任何争执，第一天就是星期天。
/** * Get week number in the year. * @param {Integer} [weekStart=0] First day of the week. 0-based. 0 for Sunday, 6 for Saturday. * @return {Integer} 0-based number of week. */ Date.prototype.getWeek = function(weekStart) { var januaryFirst = new Date(this.getFullYear(), 0, 1); if(weekStart !== undefined && (typeof weekStart !== 'number' || weekStart % 1 !== 0 || weekStart < 0 || weekStart > 6)) { throw new Error('Wrong argument. Must be an integer between 0 and 6.'); } weekStart = weekStart || 0; return Math.floor((((this - januaryFirst) / 86400000) + januaryFirst.getDay() - weekStart) / 7); };
获取任何给定date的周数
function week(year,month,day) { function serial(days) { return 86400000*days; } function dateserial(year,month,day) { return (new Date(year,month-1,day).valueOf()); } function weekday(date) { return (new Date(date)).getDay()+1; } function yearserial(date) { return (new Date(date)).getFullYear(); } var date = year instanceof Date ? year.valueOf() : typeof year === "string" ? new Date(year).valueOf() : dateserial(year,month,day), date2 = dateserial(yearserial(date - serial(weekday(date-serial(1))) + serial(4)),1,3); return ~~((date - date2 + serial(weekday(date2) + 5))/ serial(7)); }
例
console.log( week(2016, 06, 11),//23 week(2015, 9, 26),//39 week(2016, 1, 1),//53 week(2016, 1, 4),//1 week(new Date(2016, 0, 4)),//1 week("11 january 2016")//2 );
如果您已经在Angular项目中，可以使用$filter('date') 。
例如：
var myDate = new Date(); var myWeek = $filter('date')(myDate, 'ww');
下面的代码计算正确的ISO 8601周数。 它与每个星期之间的PHP date("W")在1/1/1970和1/1/2100之间匹配。
/** * Get the ISO week date week number */ Date.prototype.getWeek = function () { // Create a copy of this date object var target = new Date(this.valueOf()); // ISO week date weeks start on Monday, so correct the day number var dayNr = (this.getDay() + 6) % 7; // ISO 8601 states that week 1 is the week with the first Thursday of that year // Set the target date to the Thursday in the target week target.setDate(target.getDate() - dayNr + 3); // Store the millisecond value of the target date var firstThursday = target.valueOf(); // Set the target to the first Thursday of the year // First, set the target to January 1st target.setMonth(0, 1); // Not a Thursday? Correct the date to the next Thursday if (target.getDay() !== 4) { target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7); } // The week number is the number of weeks between the first Thursday of the year // and the Thursday in the target week (604800000 = 7 * 24 * 3600 * 1000) return 1 + Math.ceil((firstThursday - target) / 604800000); }
来源： Taco van den Broek
如果你不想扩展原型，那么这里有一个函数：
function getWeek(date) { if (!(date instanceof Date)) date = new Date(); // ISO week date weeks start on Monday, so correct the day number var nDay = (date.getDay() + 6) % 7; // ISO 8601 states that week 1 is the week with the first Thursday of that year // Set the target date to the Thursday in the target week date.setDate(date.getDate() - nDay + 3); // Store the millisecond value of the target date var n1stThursday = date.valueOf(); // Set the target to the first Thursday of the year // First, set the target to January 1st date.setMonth(0, 1); // Not a Thursday? Correct the date to the next Thursday if (date.getDay() !== 4) { date.setMonth(0, 1 + ((4 - date.getDay()) + 7) % 7); } // The week number is the number of weeks between the first Thursday of the year // and the Thursday in the target week (604800000 = 7 * 24 * 3600 * 1000) return 1 + Math.ceil((n1stThursday - date) / 604800000); }
示例用法：
getWeek(); // Returns 37 (or whatever the current week is) getWeek(new Date('Jan 2, 2011')); // Returns 52 getWeek(new Date('Jan 1, 2016')); // Returns 53 getWeek(new Date('Jan 4, 2016')); // Returns 1
这个星期的事情已经成为一个真正的痛苦**。 networking上的大多数脚本都不适合我。 他们大部分时间都在工作，但是他们都在某种程度上被打破了，特别是在年份发生变化的时候，而且上个星期突然在明年的第一周等等。甚至Angular的datefilter也显示了不正确的数据（这是明年的第一周，第53周）。
注意：例子被devise用于欧洲周（星期一）！
getWeek（）
Date.prototype.getWeek = function(){ // current week's Thursday var curWeek = new Date(this.getTime()); curWeek.setDay(4); // Get year's first week's Thursday var firstWeek = new Date(curWeek.getFullYear(), 0, 4); firstWeek.setDay(4); return (curWeek.getDayIndex() - firstWeek.getDayIndex()) / 7 + 1; };
setDay（）
/** * Make a setDay() prototype for Date * Sets week day for the date */ Date.prototype.setDay = function(day){ // Get day and make Sunday to 7 var weekDay = this.getDay() || 7; var distance = day - weekDay; this.setDate(this.getDate() + distance); return this; }
getDayIndex（）
/* * Returns index of given date (from Jan 1st) */ Date.prototype.getDayIndex = function(){ var start = new Date(this.getFullYear(), 0, 0); var diff = this - start; var oneDay = 86400000; return Math.floor(diff / oneDay); };
我已经testing了这个，它似乎工作得很好，但如果你注意到它的缺陷，请让我知道。
这里是我用JavaScript计算星期数的实现。 校正夏季和冬季时间偏移以及。 我从这篇文章中使用了本周的定义： ISO 8601
星期从星期一到星期天，一月四号总是在一年的第一个星期。
// add get week prototype functions // weeks always start from monday to sunday // january 4th is always in the first week of the year Date.prototype.getWeek = function () { year = this.getFullYear(); var currentDotw = this.getWeekDay(); if (this.getMonth() == 11 && this.getDate() - currentDotw > 28) { // if true, the week is part of next year return this.getWeekForYear(year + 1); } if (this.getMonth() == 0 && this.getDate() + 6 - currentDotw < 4) { // if true, the week is part of previous year return this.getWeekForYear(year - 1); } return this.getWeekForYear(year); } // returns a zero based day, where monday = 0 // all weeks start with monday Date.prototype.getWeekDay = function () { return (this.getDay() + 6) % 7; } // corrected for summer/winter time Date.prototype.getWeekForYear = function (year) { var currentDotw = this.getWeekDay(); var fourjan = new Date(year, 0, 4); var firstDotw = fourjan.getWeekDay(); var dayTotal = this.getDaysDifferenceCorrected(fourjan) // the difference in days between the two dates. // correct for the days of the week dayTotal += firstDotw; // the difference between the current date and the first monday of the first week, dayTotal -= currentDotw; // the difference between the first monday and the current week's monday // day total should be a multiple of 7 now var weeknumber = dayTotal / 7 + 1; // add one since it gives a zero based week number. return weeknumber; } // corrected for timezones and offset Date.prototype.getDaysDifferenceCorrected = function (other) { var millisecondsDifference = (this - other); // correct for offset difference. offsets are in minutes, the difference is in milliseconds millisecondsDifference += (other.getTimezoneOffset()- this.getTimezoneOffset()) * 60000; // return day total. 1 day is 86400000 milliseconds, floor the value to return only full days return Math.floor(millisecondsDifference / 86400000); }
为了testing，我在Qunit中使用了下面的JavaScripttesting
var runweekcompare = function(result, expected) { equal(result, expected,'Week nr expected value: ' + expected + ' Actual value: ' + result); } test('first week number test', function () { expect(5); var temp = new Date(2016, 0, 4); // is the monday of the first week of the year runweekcompare(temp.getWeek(), 1); var temp = new Date(2016, 0, 4, 23, 50); // is the monday of the first week of the year runweekcompare(temp.getWeek(), 1); var temp = new Date(2016, 0, 10, 23, 50); // is the sunday of the first week of the year runweekcompare(temp.getWeek(), 1); var temp = new Date(2016, 0, 11, 23, 50); // is the second week of the year runweekcompare(temp.getWeek(), 2); var temp = new Date(2016, 1, 29, 23, 50); // is the 9th week of the year runweekcompare(temp.getWeek(), 9); }); test('first day is part of last years last week', function () { expect(2); var temp = new Date(2016, 0, 1, 23, 50); // is the first last week of the previous year runweekcompare(temp.getWeek(), 53); var temp = new Date(2011, 0, 2, 23, 50); // is the first last week of the previous year runweekcompare(temp.getWeek(), 52); }); test('last day is part of next years first week', function () { var temp = new Date(2013, 11, 30); // is part of the first week of 2014 runweekcompare(temp.getWeek(), 1); }); test('summer winter time change', function () { expect(2); var temp = new Date(2000, 2, 26); runweekcompare(temp.getWeek(), 12); var temp = new Date(2000, 2, 27); runweekcompare(temp.getWeek(), 13); }); test('full 20 year test', function () { //expect(20 * 12 * 28 * 2); for (i = 2000; i < 2020; i++) { for (month = 0; month < 12; month++) { for (day = 1; day < 29 ; day++) { var temp = new Date(i, month, day); var expectedweek = temp.getWeek(); var temp2 = new Date(i, month, day, 23, 50); var resultweek = temp.getWeek(); equal(expectedweek, Math.round(expectedweek), 'week number whole number expected ' + Math.round(expectedweek) + ' resulted week nr ' + expectedweek); equal(resultweek, expectedweek, 'Week nr expected value: ' + expectedweek + ' Actual value: ' + resultweek + ' for year ' + i + ' month ' + month + ' day ' + day); } } } });
now = new Date(); today = new Date(now.getFullYear(), now.getMonth(), now.getDate()); firstOfYear = new Date(now.getFullYear(), 0, 1); numOfWeek = Math.ceil((((today - firstOfYear) / 86400000)-1)/7);
