JS帮你计算属相

/**
 * 该方法只能正确判定到2099年
 * @auther 黑MAO
 * @time 2014年7月19日
 */
;(function(window){
 
 /**
  * 生肖构造函数，默认参数是当前日期
  * @param {Number} year 年
  * @param {Number} month 月
  * @param {Number} day 日
  */
 function Zodiac(year, month, day) {
  var date = new Date();
  this.year = year*1 || date.getFullYear();
  this.month = month*1 || date.getMonth();
  this.day = day*1 || date.getDate();
 }
 
 Zodiac.constructor = Zodiac;
 
 /**
  * 获取C值
  * @return {Number} C
  */
 Zodiac.prototype.getC = function(){
  var _year = Math.floor(this.year/100)+1;
  var C;
 
  switch(_year){
   case 20:
    C = 4.6295;
    break;
   case 21:
    C = 3.87;
    break;
   case 22:
    C = 4.15;
    break;
   default:
    C = 3.87;
  }
  return C;
 }
 
 /**
  * 获取立春日 一般都在2月
  * @return {Number} springDay
  */
 Zodiac.prototype.getSpringDay = function(){
  var Y = this.year%100,
   D = 0.2422,
   C = this.getC(),
   L = (Y-1)/4,
   springDay = 0;
  springDay = Math.floor(Y*D+C)-Math.floor((Y-1)/4);
  return springDay;
 }
 
 /**
  * 获取生肖
  * @return {String} myZodiac
  */
 Zodiac.prototype.getZodiac = function(){
  var year = this.year,
   month = this.month,
   day = this.day,
   zodiac = [‘子鼠‘,‘丑牛‘,‘寅虎‘,‘卯兔‘,‘辰龙‘,‘巳蛇‘,‘午马‘,‘未羊‘,‘申猴‘,‘酉鸡‘,‘戌狗‘,‘亥猪‘],
   myPos = (year-1900)%12,
   myZodiac = zodiac[myPos],
   springDay = this.getSpringDay();
 
  switch(month){
   case 1:
    var _myPos = myPos-1;
    if(_myPos<0){
     _myPos = 11;
    }
    myZodiac = zodiac[_myPos];
    break;
   case 2:
    if(day < springDay){
     var _myPos = myPos-1;
     if(_myPos<0){
      _myPos = 11;
     }
     myZodiac = zodiac[_myPos];
    }
    break;
  }
  return myZodiac;
 }
 
 window.Zodiac = Zodiac;
})(window);

//默认参数是当前日期
var zodiac = new Zodiac();
//var zodiac = new Zodiac(1980, 2, 3);
//获取立春日
 console.log(zodiac.getSpringDay());
//获取生肖
 console.log(zodiac.getZodiac());
//可以与万年历进行比对
for(var year = 1900; year < 2100; year++) {
  var zodiac = new Zodiac(year, 2, 4);
  console.log(year, zodiac.getSpringDay(),zodiac.getZodiac());
 }