本文提供了一段完整的 JavaScript 代码，用于将公历日期转换为农历日期。代码包含了农历数据数组、干支纪年算法以及月份天数处理逻辑，支持 1921 年至 2020 年之间的日期转换，并展示了如何在页面加载时调用该功能获取当前日期的农历表示。
JavaScript 农历转换代码实现
具体实现代码如下所示：
<script type="text/javascript">
var CalendarData = new Array(100);
var madd = new Array(12);
var tgString = "甲乙丙丁戊己庚辛壬癸";
var dzString = "子丑寅卯辰巳午未申酉戌亥";
var numString = "一二三四五六七八九十";
var monString = "正二三四五六七八九十冬腊";
var weekString = "日一二三四五六";
var sx = "鼠牛虎兔龙蛇马羊猴鸡狗猪";
var cYear, cMonth, cDay, TheDate;
CalendarData = new Array(0xA4B, 0x5164B, 0x6A5, 0x6D4, 0x415B5, 0x2B6, 0x957, 0x2092F, 0x497, 0x60C96, 0xD4A, 0xEA5, 0x50DA9, 0x5AD, 0x2B6, 0x3126E, 0x92E, 0x7192D, 0xC95, 0xD4A, 0x61B4A, 0xB55, 0x56A, 0x4155B, 0x25D, 0x92D, 0x2192B, 0xA95, 0x71695, 0x6CA, 0xB55, 0x50AB5, 0x4DA, 0xA5B, 0x30A57, 0x52B, 0x8152A, 0xE95, 0x6AA, 0x615AA, 0xAB5, 0x4B6, 0x414AE, 0xA57, 0x526, 0x31D26, 0xD95, 0x70B55, 0x56A, 0x96D, 0x5095D, 0x4AD, 0xA4D, 0x41A4D, 0xD25, 0x81AA5, 0xB54, 0xB6A, 0x612DA, 0x95B, 0x49B, 0x41497, 0xA4B, 0xA164B, 0x6A5, 0x6D4, 0x615B4, 0xAB6, 0x957, 0x5092F, 0x497, 0x64B, 0x30D4A, 0xEA5, 0x80D65, 0x5AC, 0xAB6, 0x5126D, 0x92E, 0xC96, 0x41A95, 0xD4A, 0xDA5, 0x20B55, 0x56A, 0x7155B, 0x25D, 0x92D, 0x5192B, 0xA95, 0xB4A, 0x416AA, 0xAD5, 0x90AB5, 0x4BA, 0xA5B, 0x60A57, 0x52B, 0xA93, 0x40E95);
madd[0] = 0;
madd[1] = 31;
madd[2] = 59;
madd[3] = 90;
madd[4] = 120;
madd[5] = 151;
madd[6] = 181;
madd[7] = 212;
madd[8] = 243;
madd[9] = 273;
madd[10] = 304;
madd[11] = 334;
function GetBit(m, n) {\n return (m >> n) & 1;\n }\n function e2c() {\n TheDate = (arguments.length != 3) ? new Date() : new Date(arguments[0], arguments[1], arguments[2]);\n var total, m, n, k;\n var isEnd = false;\n var tmp = TheDate.getYear();\n if (tmp < 1900) {\n tmp += 1900;\n }\n total = (tmp - 1921) * 365 + Math.floor((tmp - 1921) / 4) + madd[TheDate.getMonth()] + TheDate.getDate() - 38;
if (TheDate.getYear() % 4 == 0 && TheDate.getMonth() > 1) {\n total++;\n }\n for (m = 0; ; m++) {\n k = (CalendarData[m] < 0xfff) ? 11 : 12;\n for (n = k; n >= 0; n--) {\n if (total <= 29 + GetBit(CalendarData[m], n)) {\n isEnd = true; break;\n }\n total = total - 29 - GetBit(CalendarData[m], n);\n }\n if (isEnd) break;\n }\n cYear = 1921 + m;\n cMonth = k - n + 1;\n cDay = total;\n if (k == 12) {\n if (cMonth == Math.floor(CalendarData[m] / 0x10000) + 1) {\n cMonth = 1 - cMonth;\n }\n if (cMonth > Math.floor(CalendarData[m] / 0x10000) + 1) {\n cMonth--;\n }\n }\n }
function GetcDateString() {\n var tmp = "";\n tmp += tgString.charAt((cYear - 4) % 10);\n tmp += dzString.charAt((cYear - 4) % 12);\n tmp += "(";\n tmp += sx.charAt((cYear - 4) % 12);\n tmp += ")年 ";\n if (cMonth < 1) {\n tmp += "(闰)";\n tmp += monString.charAt(-cMonth - 1);\n } else {\n tmp += monString.charAt(cMonth - 1);\n }\n tmp += "月";\n tmp += (cDay < 11) ? "初" : ((cDay < 20) ? "十" : ((cDay < 30) ? "廿" : "三十"));\n if (cDay % 10 != 0 || cDay == 10) {\n tmp += numString.charAt((cDay - 1) % 10);\n }\n return tmp;\n }
function GetLunarDay(solarYear, solarMonth, solarDay) {\n //solarYear = solarYear<1900?(1900+solarYear):solarYear;\n if (solarYear < 1921 || solarYear > 2020) {\n return "";\n } else {\n solarMonth = (parseInt(solarMonth) > 0) ? (solarMonth - 1) : 11;\n e2c(solarYear, solarMonth, solarDay);\n return GetcDateString();\n }\n }\n //调用\n var D = new Date();\n var yy = D.getFullYear();\n var mm = D.getMonth() + 1;\n var dd = D.getDate();\n var ww = D.getDay();\n var ss = parseInt(D.getTime() / 1000);\n if (yy < 100) yy = "19" + yy;\n function GetCNDate() {\n return GetLunarDay(yy, mm, dd);\n }\n $(document).ready(function () {\n var d = GetCNDate();\n alert(d);\n });\n</script>