(function () {
   var datepicker = {};
    datepicker.getMonthData = function (year,month) {
        var ret = [];
        if(!year || !month){
            var today = new Date();
            year = today.getFullYear();
            month = today.getMonth()+1;
        }
        var firstDay = new Date(year,month-1,1);
        var firstDayWeekDay = firstDay.getDay();
        if(firstDayWeekDay === 0)
            firstDayWeekDay = 7;

        var lastDayOfLastMonth = new Date(year,month-1,0);
        var lastDateOfLastMonth = lastDayOfLastMonth.getDate();

        var preMonthDayCount = firstDayWeekDay -1;

        var lastDay = new Date(year,month,0);
        var lastDate = lastDay.getDate();

        //利用循环查询到一周日期
        for( var i = 0; i<7*6; i++){
            var date = i+1 - preMonthDayCount;
            var showDate = date;
            var thisMonth = month;
            if(date <= 0){
                thisMonth = month +1;
                showDate = lastDateOfLastMonth +date;
            }else if(date > lastDate){
                thisMonth = month +1;
                showDate = showDate-lastDate;
            }if(thisMonth === 0)thisMonth = 12;
            if(thisMonth === 13) thisMonth = 1;

            ret.push({
               month:thisMonth,
               date:date,
                showDate:showDate
            });
        }
        return ret;
    };
   window.datepicker = datepicker;

})();

一、为了防止模块编写的时候污染环境，就会用匿名函数。