js获取上个月日期

javascript根据当前日期获取上个月日期

 function lastMonthDate(){
     var Nowdate = new Date();
     var vYear = Nowdate.getFullYear();
     var vMon = Nowdate.getMonth() + 1;
     var vDay = Nowdate.getDate();
 　　//每个月的最后一天日期（为了使用月份便于查找，数组第一位设为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;
     }
 　　//若是闰年，二月最后一天是29号
     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;
 }