php 根据给定的年份和月份获取该年份该月份的起始和结束时间

function getShiJianChuo($nian=0,$yue=0){
        if(empty($nian) || empty($yue)){
            $now = time();
            $nian = date("Y",$now);
            $yue =  date("m",$now);
        }
        $time[‘begin‘] = mktime(0,0,0,$yue,1,$nian);
        $time[‘end‘] = mktime(23,59,59,($yue+1),0,$nian);
        return $time;
    }