php获取 本月 本周 或者 下月 下周的 开始时间 结束时间

<span <span <?php<br />$now_time</span> = <span time</span><span ();
</span><span $date</span>=<span date</span>("Y-m-d",<span $now_time</span><span );
</span><span function</span> get_date(<span $date</span>,<span $t</span>='d',<span $n</span>=0<span )
{
    </span><span if</span>(<span $t</span>=='d'<span ){
       </span><span $firstday</span> = <span date</span>('Y-m-d 00:00:00',<span strtotime</span>("<span $n</span> day"<span ));
       </span><span $lastday</span> = <span date</span>("Y-m-d 23:59:59",<span strtotime</span>("<span $n</span> day"<span ));
    }</span><span elseif</span>(<span $t</span>=='w'<span ){
       </span><span if</span>(<span $n</span>!=0){<span $date</span> = <span date</span>('Y-m-d',<span strtotime</span>("<span $n</span> week"<span ));}
       </span><span $lastday</span> = <span date</span>("Y-m-d 00:00:00",<span strtotime</span>("<span $date</span> Sunday"<span ));
       </span><span $firstday</span> = <span date</span>("Y-m-d 23:59:59",<span strtotime</span>("<span $lastday</span> -6 days"<span ));
    }</span><span elseif</span>(<span $t</span>=='m'<span ){
       </span><span if</span>(<span $n</span>!=0){<span $date</span> = <span date</span>('Y-m-d',<span strtotime</span>("<span $n</span> months"<span ));}
       </span><span $firstday</span> = <span date</span>("Y-m-01 00:00:00",<span strtotime</span>(<span $date</span><span ));
       </span><span $lastday</span> = <span date</span>("Y-m-d 23:59:59",<span strtotime</span>("<span $firstday</span> +1 month -1 day"<span )); 
    }
    </span><span return</span> <span array</span>(<span $firstday</span>,<span $lastday</span><span );
}
</span><span $day1</span>   = get_date(<span $date</span>,'d'<span );
</span><span $day2</span>   = get_date(<span $date</span>,'d',-1<span );
</span><span $week1</span> = get_date(<span $date</span>,'w'<span );
</span><span $week2</span> = get_date(<span $date</span>,'w',-1<span );
</span><span $month1</span> = get_date(<span $date</span>,'m'<span );
</span><span $month2</span> = get_date(<span $date</span>,'m',-1<span );
</span><span echo</span> '<pre class="brush:php;toolbar:false;">'<span ;
</span><span print_r</span>(<span $day1</span>);<span //</span><span 今天</span>
<span print_r</span>(<span $day2</span>);<span //</span><span 昨天</span>
<span print_r</span>(<span $week1</span>);<span //</span><span 这周</span>
<span print_r</span>(<span $week2</span>);<span //</span><span 上周</span>
<span print_r</span>(<span $month1</span>);<span //</span><span 这月</span>
<span print_r</span>(<span $month2</span>);<span //</span><span 上月</span>
<span echo</span> '