获取当前栏目ID

<?php
$a = $GLOBALS['navclassid'];
?>

获取当前栏目的上级栏目ID

<?php
$a = $GLOBALS['navclassid'];
$b = $class_r[$a]['bclassid'];
?>

获取上上级栏目ID和顶级栏目ID

<?php
$aa = $GLOBALS['navclassid'];
$bb = $class_r[$aa]['bclassid'];
$cc = $class_r[$bb]['bclassid'];
$dd = $class_r[$cc]['bclassid'];
?>