利用Date对象编写程序，判断并输出今天是开学的第几周，星期几。

(function(){

var startDay = new Date(2014,8,1);        //根据指定的年月日时分秒设置开学时间为2014/09/01

var startMs = startDay.getTime();//返回1970年至今的毫秒

var startYear = startDay.getFullYear();//从Date对象以四位数字返回年份

var startMonth = startDay.getMonth()+1;    //从Date对象返回年份(0-11)

var startDate = startDay.getDate();        // 从Date对象返回一月中的某一天(1~31)

var nowDay = new Date();

var nowMs = nowDay.getTime();

var nowYear = nowDay.getFullYear();

var nowMonth = nowDay.getMonth()+1;

var nowDate = nowDay.getDate();

var startDays = parseInt(startMs/86400000);

var nowDays = parseInt(nowMs/86400000);

var totalDays = nowDays - startDays;

var week = parseInt(totalDays/7)+1;

var nowdate = nowDay.getDay();

msg1 = "开学时间：" + startYear + " 年 " + startMonth + " 月 " + startDate + "日";

document.write(msg1);

document.write("
")

msg2 ="现在时间：" + nowYear + " 年 " + nowMonth + " 月 " + nowDate + "日";

document.write(msg2);

document.write("
");

msg3 =  "第" + week + "周，星期" + nowdate;

document.write(msg3);

})();