我正在用 JavaScript 制作日历生成器。我需要给定年份的复活节午夜的 Unix 时间戳。我该怎么做（在 JavaScript 中）？
PHP的函数可以在here.
中找到根据这个：-
function Easter(Y) {
var C = Math.floor(Y/100);
var N = Y - 19*Math.floor(Y/19);
var K = Math.floor((C - 17)/25);
var I = C - Math.floor(C/4) - Math.floor((C - K)/3) + 19*N + 15;
I = I - 30*Math.floor((I/30));
I = I - Math.floor(I/28)*(1 - Math.floor(I/28)*Math.floor(29/(I + 1))*Math.floor((21 - N)/11));
var J = Y + Math.floor(Y/4) + I + 2 - C + Math.floor(C/4);
J = J - 7*Math.floor(J/7);
var L = I - J;
var M = 3 + Math.floor((L + 40)/44);
var D = L + 28 - 31*Math.floor(M/4);
return padout(M) + '.' + padout(D);
}
function padout(number) { return (number < 10) ? '0' + number : number; }
用法示例：-
document.write(Easter(1997));
这是一种替代方法，该方法基于 R. Sivaraman 从最初由 J. Meeus 为儒略历开发的算法改编为公历的算法（参见 https://en.wikipedia.org/wiki/Computus） .
这似乎是比已经提到的高斯算法更优雅和直观的解决方案。至少它减少了几个步骤（总共只有 5 个步骤加上 JS date 方法）并且使用更少的变量（总共只有 4 个步骤加上月份、日期和年份）。
function computus( y ) {
var date, a, b, c, m, d;
// Instantiate the date object.
date = new Date;
// Set the timestamp to midnight.
date.setHours( 0, 0, 0, 0 );
// Set the year.
date.setFullYear( y );
// Find the golden number.
a = y % 19;
// Choose which version of the algorithm to use based on the given year.
b = ( 2200 <= y && y <= 2299 ) ?
( ( 11 * a ) + 4 ) % 30 :
( ( 11 * a ) + 5 ) % 30;
// Determine whether or not to compensate for the previous step.
c = ( ( b === 0 ) || ( b === 1 && a > 10 ) ) ?
( b + 1 ) :
b;
// Use c first to find the month: April or March.
m = ( 1 <= c && c <= 19 ) ? 3 : 2;
// Then use c to find the full moon after the northward equinox.
d = ( 50 - c ) % 31;
// Mark the date of that full moon—the "Paschal" full moon.
date.setMonth( m, d );
// Count forward the number of days until the following Sunday (Easter).
date.setMonth( m, d + ( 7 - date.getDay() ) );
// Gregorian Western Easter Sunday
return date;
}
例如：
console.log( computus( 2016 ) ); // Date 2016-03-27T05:00:00.000Z
以下基于Laurent Longre算法
从1583年（公历开始）开始工作
输出为
[year, month, day]//===========================================================
function easterDateLLongre(Y) {
let M=3, G= Y % 19+1, C= ~~(Y/100)+1, L=~~((3*C)/4)-12,
E=(11*G+20+ ~~((8*C+5)/25)-5-L)%30, D;
E<0 && (E+=30);
(E==25 && G>11 || E==24) && E++;
(D=44-E)<21 && (D+=30);
(D+=7-(~~((5*Y)/4)-L-10+D)%7)>31 && (D-=31,M=4);
return [Y, M, D];
}
//===========================================================
//======================= Tests =====================
console.log(easterDateLLongre(1583)); // [1583, 4, 10]
console.log(easterDateLLongre(1853)); // [1853, 3, 27]
console.log(easterDateLLongre(2021)); // [2021, 4, 4]
console.log(easterDateLLongre(2700)); // [2700, 4, 1]如果您需要知道现在是否是复活节（星期日），您可以使用此功能。 （这是我搜索的内容）：
function isEasterSunday() {
var curdate = new Date();
var year = curdate.getFullYear();
var a = year % 19;
var b = Math.floor(year / 100);
var c = year % 100;
var d = Math.floor(b / 4);
var e = b % 4;
var f = Math.floor((b + 8) / 25);
var g = Math.floor((b - f + 1) / 3);
var h = (19 * a + b - d - g + 15) % 30;
var i = Math.floor(c / 4);
var k = c % 4;
var l = (32 + 2 * e + 2 * i - h - k) % 7;
var m = Math.floor((a + 11 * h + 22 * l) / 451);
var n0 = (h + l + 7 * m + 114)
var n = Math.floor(n0 / 31) - 1;
var p = n0 % 31 + 1;
var date = new Date(year,n,p);
return ((curdate.getMonth() == date.getMonth())&&(curdate.getDate() == date.getDate()));
}
不知道其他答案有多准确，但是这个答案/包是一个js端口，来自为Moontool for Windows提供动力的方程式，众所周知是可信的。
如果你只是想要普通的js，你可以复制/粘贴这段代码。你会想要使用
getEaster(year)getEaster(2020)Datevar epoch=2444238.5,elonge=278.83354,elongp=282.596403,eccent=.016718,sunsmax=149598500,sunangsiz=.533128,mmlong=64.975464,mmlongp=349.383063,mlnode=151.950429,minc=5.145396,mecc=.0549,mangsiz=.5181,msmax=384401,mparallax=.9507,synmonth=29.53058868,lunatbase=2423436,earthrad=6378.16,PI=3.141592653589793,epsilon=1e-6;function sgn(x){return x<0?-1:x>0?1:0}function abs(x){return x<0?-x:x}function fixAngle(a){return a-360*Math.floor(a/360)}function toRad(d){return d*(PI/180)}function toDeg(d){return d*(180/PI)}function dsin(x){return Math.sin(toRad(x))}function dcos(x){return Math.cos(toRad(x))}function toJulianTime(date){var year,month,day;year=date.getFullYear();var m=(month=date.getMonth()+1)>2?month:month+12,y=month>2?year:year-1,d=(day=date.getDate())+date.getHours()/24+date.getMinutes()/1440+(date.getSeconds()+date.getMilliseconds()/1e3)/86400,b=isJulianDate(year,month,day)?0:2-y/100+y/100/4;return Math.floor(365.25*(y+4716)+Math.floor(30.6001*(m+1))+d+b-1524.5)}function isJulianDate(year,month,day){if(year<1582)return!0;if(year>1582)return!1;if(month<10)return!0;if(month>10)return!1;if(day<5)return!0;if(day>14)return!1;throw"Any date in the range 10/5/1582 to 10/14/1582 is invalid!"}function jyear(td,yy,mm,dd){var z,f,alpha,b,c,d,e;return f=(td+=.5)-(z=Math.floor(td)),b=(z<2299161?z:z+1+(alpha=Math.floor((z-1867216.25)/36524.25))-Math.floor(alpha/4))+1524,c=Math.floor((b-122.1)/365.25),d=Math.floor(365.25*c),e=Math.floor((b-d)/30.6001),{day:Math.floor(b-d-Math.floor(30.6001*e)+f),month:Math.floor(e<14?e-1:e-13),year:Math.floor(mm>2?c-4716:c-4715)}}function jhms(j){var ij;return j+=.5,ij=Math.floor(86400*(j-Math.floor(j))+.5),{hour:Math.floor(ij/3600),minute:Math.floor(ij/60%60),second:Math.floor(ij%60)}}function jwday(j){return Math.floor(j+1.5)%7}function meanphase(sdate,k){var t,t2;return 2415020.75933+synmonth*k+1178e-7*(t2=(t=(sdate-2415020)/36525)*t)-155e-9*(t2*t)+33e-5*dsin(166.56+132.87*t-.009173*t2)}function truephase(k,phase){var t,t2,t3,pt,m,mprime,f,apcor=!1;if(pt=2415020.75933+synmonth*(k+=phase)+1178e-7*(t2=(t=k/1236.85)*t)-155e-9*(t3=t2*t)+33e-5*dsin(166.56+132.87*t-.009173*t2),m=359.2242+29.10535608*k-333e-7*t2-347e-8*t3,mprime=306.0253+385.81691806*k+.0107306*t2+1236e-8*t3,f=21.2964+390.67050646*k-.0016528*t2-239e-8*t3,phase<.01||abs(phase-.5)<.01?(pt+=(.1734-393e-6*t)*dsin(m)+.0021*dsin(2*m)-.4068*dsin(mprime)+.0161*dsin(2*mprime)-4e-4*dsin(3*mprime)+.0104*dsin(2*f)-.0051*dsin(m+mprime)-.0074*dsin(m-mprime)+4e-4*dsin(2*f+m)-4e-4*dsin(2*f-m)-6e-4*dsin(2*f+mprime)+.001*dsin(2*f-mprime)+5e-4*dsin(m+2*mprime),apcor=!0):(abs(phase-.25)<.01||abs(phase-.75)<.01)&&(pt+=(.1721-4e-4*t)*dsin(m)+.0021*dsin(2*m)-.628*dsin(mprime)+.0089*dsin(2*mprime)-4e-4*dsin(3*mprime)+.0079*dsin(2*f)-.0119*dsin(m+mprime)-.0047*dsin(m-mprime)+3e-4*dsin(2*f+m)-4e-4*dsin(2*f-m)-6e-4*dsin(2*f+mprime)+.0021*dsin(2*f-mprime)+3e-4*dsin(m+2*mprime)+4e-4*dsin(m-2*mprime)-3e-4*dsin(2*m+mprime),pt+=phase<.5?.0028-4e-4*dcos(m)+3e-4*dcos(mprime):4e-4*dcos(m)-.0028-3e-4*dcos(mprime),apcor=!0),!apcor)throw"Error calculating moon phase!";return pt}function phasehunt(sdate,phases){var adate,k1,k2,nt1,nt2,yy,mm,dd,jyearResult=jyear(adate=sdate-45,yy,mm,dd);for(yy=jyearResult.year,mm=jyearResult.month,dd=jyearResult.day,adate=nt1=meanphase(adate,k1=Math.floor(12.3685*(yy+1/12*(mm-1)-1900)));nt2=meanphase(adate+=synmonth,k2=k1+1),!(nt1<=sdate&&nt2>sdate);)nt1=nt2,k1=k2;return phases[0]=truephase(k1,0),phases[1]=truephase(k1,.25),phases[2]=truephase(k1,.5),phases[3]=truephase(k1,.75),phases[4]=truephase(k2,0),phases}function kepler(m,ecc){var e,delta;e=m=toRad(m);do{e-=(delta=e-ecc*Math.sin(e)-m)/(1-ecc*Math.cos(e))}while(abs(delta)>epsilon);return e}function getMoonPhase(julianDate){var Day,N,M,Ec,Lambdasun,ml,MM,MN,Ev,Ae,MmP,mEc,lP,lPP,NP,y,x,MoonAge,MoonPhase,MoonDist,MoonDFrac,MoonAng,F,SunDist,SunAng;return N=fixAngle(360/365.2422*(Day=julianDate-epoch)),Ec=kepler(M=fixAngle(N+elonge-elongp),eccent),Ec=Math.sqrt((1+eccent)/(1-eccent))*Math.tan(Ec/2),Lambdasun=fixAngle((Ec=2*toDeg(Math.atan(Ec)))+elongp),F=(1+eccent*Math.cos(toRad(Ec)))/(1-eccent*eccent),SunDist=sunsmax/F,SunAng=F*sunangsiz,ml=fixAngle(13.1763966*Day+mmlong),MM=fixAngle(ml-.1114041*Day-mmlongp),MN=fixAngle(mlnode-.0529539*Day),MmP=MM+(Ev=1.2739*Math.sin(toRad(2*(ml-Lambdasun)-MM)))-(Ae=.1858*Math.sin(toRad(M)))-.37*Math.sin(toRad(M)),lPP=(lP=ml+Ev+(mEc=6.2886*Math.sin(toRad(MmP)))-Ae+.214*Math.sin(toRad(2*MmP)))+.6583*Math.sin(toRad(2*(lP-Lambdasun))),NP=MN-.16*Math.sin(toRad(M)),y=Math.sin(toRad(lPP-NP))*Math.cos(toRad(minc)),x=Math.cos(toRad(lPP-NP)),toDeg(Math.atan2(y,x)),NP,toDeg(Math.asin(Math.sin(toRad(lPP-NP))*Math.sin(toRad(minc)))),MoonAge=lPP-Lambdasun,MoonPhase=(1-Math.cos(toRad(MoonAge)))/2,MoonDist=msmax*(1-mecc*mecc)/(1+mecc*Math.cos(toRad(MmP+mEc))),MoonAng=mangsiz/(MoonDFrac=MoonDist/msmax),mparallax/MoonDFrac,{moonIllumination:MoonPhase,moonAgeInDays:synmonth*(fixAngle(MoonAge)/360),distanceInKm:MoonDist,angularDiameterInDeg:MoonAng,distanceToSun:SunDist,sunAngularDiameter:SunAng,moonPhase:fixAngle(MoonAge)/360}}function getMoonInfo(date){return null==date?{moonPhase:0,moonIllumination:0,moonAgeInDays:0,distanceInKm:0,angularDiameterInDeg:0,distanceToSun:0,sunAngularDiameter:0}:getMoonPhase(toJulianTime(date))}function getEaster(year){var previousMoonInfo,moonInfo,fullMoon=new Date(year,2,21),gettingDarker=void 0;do{previousMoonInfo=getMoonInfo(fullMoon),fullMoon.setDate(fullMoon.getDate()+1),moonInfo=getMoonInfo(fullMoon),void 0===gettingDarker?gettingDarker=moonInfo.moonIllumination<previousMoonInfo.moonIllumination:gettingDarker&&moonInfo.moonIllumination>previousMoonInfo.moonIllumination&&(gettingDarker=!1)}while(gettingDarker&&moonInfo.moonIllumination<previousMoonInfo.moonIllumination||!gettingDarker&&moonInfo.moonIllumination>previousMoonInfo.moonIllumination);for(fullMoon.setDate(fullMoon.getDate()-1);0!==fullMoon.getDay();)fullMoon.setDate(fullMoon.getDate()+1);return fullMoon}
即。
getEaster(2020); // -> Sun Apr 12 2020检查给定日期是否在复活节。 如果没有给出日期，则使用当前日期。 🙂
function isEaster(dateObject) {
const date = dateObject ?? new Date();
const year = date.getFullYear();
// Calculate the date of good friday for the current year
const a = year % 19;
const b = Math.floor(year / 100);
const c = year % 100;
const d = Math.floor(b / 4);
const e = b % 4;
const f = Math.floor((b + 8) / 25);
const g = Math.floor((b - f + 1) / 3);
const h = (19 * a + b - d - g + 15) % 30;
const i = Math.floor(c / 4);
const k = c % 4;
const l = (32 + 2 * e + 2 * i - h - k) % 7;
const m = Math.floor((a + 11 * h + 22 * l) / 451);
const n = Math.floor((h + l - 7 * m + 114) / 31) - 1;
const p = (h + l - 7 * m + 114) % 31;
// Calculate the easter dates
const maundyThursday = new Date(year, n, p - 1);
const goodFriday = new Date(year, n, p);
const holySaturday = new Date(year, n, p + 1);
const easterSunday = new Date(year, n, p + 2);
const easterMonday = new Date(year, n, p + 3);
return ([maundyThursday, goodFriday, holySaturday, easterSunday, easterMonday].map(elem => {
return elem.toISOString().split('T')[0];
}).indexOf(date.toISOString().split('T')[0]) > -1);
}