//time为 202108 格式
 
getNearMonth(time){
    if(time != null && time != '' " ){
      var nyYear=time.slice(0,4);
      var nyMonth=time.slice(4,time.length);
      var firstDay = new Date(nyYear,nyMonth-1);
      var lastDay = new Date(new Date(nyYear,nyMonth).valueOf()-60*60*1000*24);
      function datasFormat(d){
          var datetime=d.getFullYear() + '-' + (d.getMonth() + 1) + '-' + d.getDate();
          return datetime;
          console.log(datetime,777)
      }
      var firstDay = datasFormat(firstDay)
      var lastDay = datasFormat(lastDay)
      console.log(firstDay ,lastDay ,111)
    }
  },