Clear Node Taxonomy

if(isset($_POST['submit'])) {
$nid = $_POST['nid'];
$node = node_load($nid);
if ($node==NULL){
drupal_set_message(t($nid.' is not a valid NID'), 'error');
} else {
taxonomy_node_save($nid,array());
drupal_set_message(t('removed terms on node '.l($node->title?$node->title:$nid, "node/$nid")));
}
}
?>