function lastMonthDate(){
var Nowdate = new Date();
var vYear = Nowdate.getFullYear();
var vMon = Nowdate.getMonth() + 1;
var vDay = Nowdate.getDate();
　　//每個月的最後一天日期（為了使用月份便於查詢，陣列第一位設為0）
var daysInMonth = new Array(0,31,28,31,30,31,30,31,31,30,31,30,31);
if(vMon==1){
vYear = Nowdate.getFullYear()-1;
vMon = 12;
}else{
vMon = vMon -1;
}
　　//若是閏年，二月最後一天是29號
if(vYear%4 == 0 && vYear%100 != 0 || vYear%400 = 0 ){
daysInMonth[2]= 29;
}
if(daysInMonth[vMon] < vDay){
vDay = daysInMonth[vMon];
}
if(vDay<10){
vDay=”0”+vDay;
}
if(vMon<10){
vMon=”0”+vMon;
}
var date =vYear+”-“+ vMon +”-“+vDay;
console.log(date)
return date;
}