php 多级领航显示

	$cpath = array();	if(!empty($_REQUEST["parentId"])){		//category path		//get the category path//put current category id in $cpath		$current_category["parentId"] = $_REQUEST["parentId"];// put parent category id in $cpath 		do{array_unshift($cpath,$current_category["parentId"]);			$data_category = array(				"id" => $current_category["parentId"]			);			$current_category = array();			$current_category = pos($db_conn->search($db_category,$data_category));		}while(!empty($current_category["parentId"]));	}	//add the first level category parentId	array_unshift($cpath,"null");	// get all categories	$categories_level_count = sizeof($cpath);	for($i=0;$i $cpath[$i]		);		//get first level categories		$categories[$i] = $db_conn->search($db_category,$data_category);//		echo $db_category->search($data_category)."";	}

<ul> ?<li>      <ul>        ...      </ul> ?</li></ul>

			function show_left_navigation($i){				global $categories,$cpath;				if(empty($categories[$i]))					return;				echo '<ul>';				foreach($categories[$i] as $id=>$category){					echo '';					if($id==end($cpath))						echo '<a href="advancedSearch.php?parentId='.$id.'">'.$category["name"].'</a>';					else						echo '<a href="advancedSearch.php?parentId='.$id.'">'.$category["name"].'</a>';					if(in_array($id,$cpath))						show_left_navigation($i+1);					echo '';				}				echo '</ul>'; 			}			show_left_navigation(0);