获取顶级父类id<pre name="code" class="php">
/**
* 获取顶级父类id
* @param [type] $id [description]
* @return [type] [description]
*/
function get_top_parentid($id){
$r = M('Category')->where('id = '.$id)->field('id,parentid')->find();
if($r['parentid'] != '0') return get_top_parentid($r['parentid']);
return $r['id'];
}