مدیاویکی:Jalalical.js

JalaliDate = {
	g_days_in_month: [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
	j_days_in_month: [31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29]
};
var CalendarJMN = new Array
("فروردین",
 "اردیبهشت",
 "خرداد",
 "تیر",
 "مرداد",
 "شهریور",
 "مهر",
 "آبان",
 "آذر",
 "دی",
 "بهمن",
 "اسفند");
JalaliDate.checkDate = function(j_y, j_m, j_d)
{
	return !(j_y < 0 || j_y > 32767 || j_m < 1 || j_m > 12 || j_d < 1 || j_d >
		(JalaliDate.j_days_in_month[j_m-1] + (j_m == 12 && !((j_y-979)%33%4))));
}

JalaliDate.gregorianToJalali = function(g_y, g_m, g_d)
{
	g_y = parseInt(g_y);
	g_m = parseInt(g_m);
	g_d = parseInt(g_d);
	var gy = g_y-1600;
	var gm = g_m-1;
	var gd = g_d-1;

	var g_day_no = 365*gy+parseInt((gy+3) / 4)-parseInt((gy+99)/100)+parseInt((gy+399)/400);

	for (var i=0; i < gm; ++i)
	g_day_no += JalaliDate.g_days_in_month[i];
	if (gm>1 && ((gy%4==0 && gy%100!=0) || (gy%400==0)))
	/* leap and after Feb */
	++g_day_no;
	g_day_no += gd;

	var j_day_no = g_day_no-79;

	var j_np = parseInt(j_day_no/ 12053);
	j_day_no %= 12053;

	var jy = 979+33*j_np+4*parseInt(j_day_no/1461);

	j_day_no %= 1461;

	if (j_day_no >= 366) {
		jy += parseInt((j_day_no-1)/ 365);
		j_day_no = (j_day_no-1)%365;
	}

	for (var i = 0; i < 11 && j_day_no >= JalaliDate.j_days_in_month[i]; ++i) {
		j_day_no -= JalaliDate.j_days_in_month[i];
	}
	var jm = i;
	var jd = j_day_no+1;
	return [jy,  CalendarJMN[jm], jd];
}