phpcms V9如何实现wap上一篇、下一篇功能

if(!$r || $r['status'] != 99) showmessage(L('info_does_not_exists'),'blank');

 //上一页
$previous_page = $this->db->get_one("`catid` = '$catid' AND `id`<'$id' AND `status`=99",'*','id DESC');
//下一页
$next_page = $this->db->get_one("`catid`= '$catid' AND `id`>'$id' AND `status`=99");
if(empty($previous_page)) {
　　$previous_page = array('title'=>L('first_page'), 'thumb'=>IMG_PATH.'nopic_small.gif', 'url'=>'javascript：alert(\''.L('first_page').'\');');
}
if(empty($next_page)) {
　　$next_page = array('title'=>L('last_page'), 'thumb'=>IMG_PATH.'nopic_small.gif', 'url'=>'javascript：alert(\''.L('last_page').'\');');
}

<P><a href="{WAP_SITEURL}&a=show&catid={$catid}&typeid=1&id={$previous_page[id]}">上一篇：{$previous_page[title]}</a></P>
 <P><a href="{WAP_SITEURL}&a=show&catid={$catid}&typeid=1&id={$next_page[id]}">上一篇：{$next_page[title]}</a></P>