$firstday = date("Y-m-d H:i:s",time());//当前日期
            $timestamp=strtotime($firstday);//当前日期时间戳
            $firstday=date('Y-m-01',strtotime(date('Y',$timestamp).'-'.(date('m',$timestamp)-1).'-01'));//上个月开始的日期
            $lastday=date('Y-m-d',strtotime("$firstday +1 month -1 day"));//上个月结束的日期
            $stimestamp = strtotime($firstday);
            $etimestamp = strtotime($lastday);
            // 计算日期段内有多少天
            $days = ($etimestamp-$stimestamp)/86400+1;
            // 保存每天日期
            $date = array();
            for($i=0; $i<$days; $i++){
                $date[] = date('Y-m-d', $stimestamp+(86400*$i));
            }