javaScript日期工具类DateUtils详解

dateutils = { 
    patterns: { 
      pattern_era: 'g', //era 标志符 era strings. for example: "ad" and "bc" 
      pattern_year: 'y', //年 
      pattern_month: 'm', //月份 
      pattern_day_of_month: 'd', //月份的天数 
      pattern_hour_of_day1: 'k', //一天中的小时数（1-24） 
      pattern_hour_of_day0: 'h', //24小时制，一天中的小时数（0-23） 
      pattern_minute: 'm', //小时中的分钟数 
      pattern_second: 's', //秒 
      pattern_millisecond: 's', //毫秒 
      pattern_day_of_week: 'e', //一周中对应的星期，如星期一，周一 
      pattern_day_of_year: 'd', //一年中的第几天 
      pattern_day_of_week_in_month: 'f', //一月中的第几个星期(会把这个月总共过的天数除以7,不够准确，推荐用w) 
      pattern_week_of_year: 'w', //一年中的第几个星期 
      pattern_week_of_month: 'w', //一月中的第几星期(会根据实际情况来算) 
      pattern_am_pm: 'a', //上下午标识 
      pattern_hour1: 'h', //12小时制 ，am/pm 中的小时数（1-12） 
      pattern_hour0: 'k', //和h类型 
      pattern_zone_name: 'z', //时区名 
      pattern_zone_value: 'z', //时区值 
      pattern_week_year: 'y', //和y类型 
      pattern_iso_day_of_week: 'u', 
      pattern_iso_zone: 'x' 
    }, 
    week: { 
      'ch': { 
        "0": "\u65e5", 
        "1": "\u4e00", 
        "2": "\u4e8c", 
        "3": "\u4e09", 
        "4": "\u56db", 
        "5": "\u4e94", 
        "6": "\u516d" 
      }, 
      'en': { 
        "0": "sunday", 
        "1": "monday", 
        "2": "tuesday", 
        "3": "wednesday", 
        "4": "thursday", 
        "5": "friday", 
        "6": "saturday" 
      } 
    }, 
    //获取当前时间 
    getcurrenttime: function() { 
      var today = new date(); 
      var year = today.getfullyear(); 
      var month = today.getmonth() + 1; 
      var day = today.getdate(); 
      var hours = today.gethours(); 
      var minutes = today.getminutes(); 
      var seconds = today.getseconds(); 
      var timestring = year + "-" + month + "-" + day + " " + hours + ":" + minutes + ":" + seconds; 
      return timestring; 
    }, 
    /* 
     * 比较时间大小 
     * time1>time2 return 1 
     * time1<time2 return -1 
     * time1==time2 return 0 
     */ 
    comparetime: function(time1, time2) { 
      if(date.parse(time1.replace(/-/g, "/")) > date.parse(time2.replace(/-/g, "/"))) { 
        return 1; 
      } else if(date.parse(time1.replace(/-/g, "/")) < date.parse(time2.replace(/-/g, "/"))) { 
        return -1; 
      } else if(date.parse(time1.replace(/-/g, "/")) == date.parse(time2.replace(/-/g, "/"))) { 
        return 0; 
      } 
    }, 
    //是否闰年 
    isleapyear: function(year) { 
      return((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0); 
    }, 
    //获取某个月的天数，从0开始 
    getdaysofmonth: function(year, month) { 
      return [31, (this.isleapyear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month]; 
    }, 
    getdaysofmonth2: function(year, month) { 
      // 将天置为0，会获取其上个月的最后一天 
      month = parseint(month) + 1; 
      var date = new date(year, month, 0); 
      return date.getdate(); 
    }, 
    /*距离现在几天的日期：负数表示今天之前的日期，0表示今天，整数表示未来的日期 
     * 如-1表示昨天的日期，0表示今天，2表示后天 
     */ 
    fromtoday: function(days) { 
      var today = new date(); 
      today.setdate(today.getdate() + days); 
      var date = today.getfullyear() + "-" + (today.getmonth() + 1) + "-" + today.getdate(); 
      return date; 
    }, 
    /** 
     * 日期时间格式化 
     * @param {object} datetime 需要格式化的日期时间 
     * @param {string} pattern 格式化的模式，如yyyy-mm-dd hh(hh):mm:ss.s a k k e d f w w z z 
     */ 
    formt: function(datetime, pattern) { 
      var date = new date(datetime); 
      if(bee.stringutils.isblank(pattern)) { 
        return date.tolocalestring(); 
      } 
      return pattern.replace(/([a-z])\1*/ig, function(matchstr, group1) { 
        var replacement = ""; 
        switch(group1) { 
          case bee.dateutils.patterns.pattern_era: //g 
            break; 
          case bee.dateutils.patterns.pattern_week_year: //y 
          case bee.dateutils.patterns.pattern_year: //y 
            replacement = date.getfullyear(); 
            break; 
          case bee.dateutils.patterns.pattern_month: //m 
            var month = date.getmonth() + 1; 
            replacement = (month < 10 && matchstr.length >= 2) ? "0" + month : month; 
            break; 
          case bee.dateutils.patterns.pattern_day_of_month: //d 
            var days = date.getdate(); 
            replacement = (days < 10 && matchstr.length >= 2) ? "0" + days : days; 
            break; 
          case bee.dateutils.patterns.pattern_hour_of_day1: //k(1~24) 
            var hours24 = date.gethours(); 
            replacement = hours24; 
            break; 
          case bee.dateutils.patterns.pattern_hour_of_day0: //h(0~23) 
            var hours24 = date.gethours(); 
            replacement = (hours24 < 10 && matchstr.length >= 2) ? "0" + hours24 : hours24; 
            break; 
          case bee.dateutils.patterns.pattern_minute: //m 
            var minutes = date.getminutes(); 
            replacement = (minutes < 10 && matchstr.length >= 2) ? "0" + minutes : minutes; 
            break; 
          case bee.dateutils.patterns.pattern_second: //s 
            var seconds = date.getseconds(); 
            replacement = (seconds < 10 && matchstr.length >= 2) ? "0" + seconds : seconds; 
            break; 
          case bee.dateutils.patterns.pattern_millisecond: //s 
            var milliseconds = date.getmilliseconds(); 
            replacement = milliseconds; 
            break; 
          case bee.dateutils.patterns.pattern_day_of_week: //e 
            var day = date.getday(); 
            replacement = bee.dateutils.week['ch'][day]; 
            break; 
          case bee.dateutils.patterns.pattern_day_of_year: //d 
            replacement = bee.dateutils.dayoftheyear(date); 
            break; 
          case bee.dateutils.patterns.pattern_day_of_week_in_month: //f 
            var days = date.getdate(); 
            replacement = math.floor(days / 7); 
            break; 
          case bee.dateutils.patterns.pattern_week_of_year: //w 
            var days = bee.dateutils.dayoftheyear(date); 
            replacement = math.ceil(days / 7); 
            break; 
          case bee.dateutils.patterns.pattern_week_of_month: //w 
            var days = date.getdate(); 
            replacement = math.ceil(days / 7); 
            break; 
          case bee.dateutils.patterns.pattern_am_pm: //a 
            var hours24 = date.gethours(); 
            replacement = hours24 < 12 ? "\u4e0a\u5348" : "\u4e0b\u5348"; 
            break; 
          case bee.dateutils.patterns.pattern_hour1: //h(1~12) 
            var hours12 = date.gethours() % 12 || 12; //0转为12 
            replacement = (hours12 < 10 && matchstr.length >= 2) ? "0" + hours12 : hours12; 
            break; 
          case bee.dateutils.patterns.pattern_hour0: //k(0~11) 
            var hours12 = date.gethours() % 12; 
            replacement = hours12; 
            break; 
          case bee.dateutils.patterns.pattern_zone_name: //z 
            replacement = bee.dateutils.getzonenamevalue(date)['name']; 
            break; 
          case bee.dateutils.patterns.pattern_zone_value: //z 
            replacement = bee.dateutils.getzonenamevalue(date)['value']; 
            break; 
          case bee.dateutils.patterns.pattern_iso_day_of_week: //u 
            break; 
          case bee.dateutils.patterns.pattern_iso_zone: //x 
            break; 
          default: 
            break; 
        } 
        return replacement; 
      }); 
    }, 
    /** 
     * 计算一个日期是当年的第几天 
     * @param {object} date 
     */ 
    dayoftheyear: function(date) { 
      var obj = new date(date); 
      var year = obj.getfullyear(); 
      var month = obj.getmonth(); //从0开始 
      var days = obj.getdate(); 
      var daysarr = [31, (this.isleapyear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; 
      for(var i = 0; i < month; i++) { 
        days += daysarr[i]; 
      } 
      return days; 
    }, 
    //获得时区名和值 
    getzonenamevalue: function(dateobj) { 
      var date = new date(dateobj); 
      date = new date(date.utc(date.getfullyear(), date.getmonth(), date.getdate())); 
      var arr = date.tostring().match(/([a-z]+)([-+]\d+:?\d+)/); 
      var obj = { 
        'name': arr[1], 
        'value': arr[2] 
      }; 
      return obj; 
    } 
  };