//
// url-je a mymodule_menu()-ben: mymodule/query/tree
//
function mymodule_query_tree_form($form, &$form_state) {
 
  // SQL ***
  $query = db_query('SELECT ...');
  // $main_items ...
  // ******
 
 
  // html string for display
  $html = "<ul>";
 
  // recursive node tree
  foreach ( $main_items as $item ) {
     $html.= "<li>" . $main_names[$item];
     $html.= display_tree_node( $item );
     $html.= "</li>";
  }	// foreach
 
  $html.= "</ul>";
 
 
  // form for display
  $form = array();
 
  $form['decoration'] = array(
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#title' => t('Tree')
  );
 
  $form['#attached']['js'] = array(
    drupal_get_path('module', 'mymodule') . '/js/tree.js',
  );
 
  $form['decoration']['htmlstr'] = array(
    '#type' => 'item',
    '#markup' => $html,
  );
 
 
  return $form;
}
 
function display_tree_node($id) {
  // fastruktúra bejárása és html kód a fa struktúra megjelenítésére ul, li elemekkel
}

(function($) {
Drupal.behaviors.myBehavior = {
  attach: function (context, settings) {
 
    //code starts
    $( document ).ready(function() {
      // Handler for .ready() called.
      setInterval(function(){refresh();}, 10000);
    });
 
 
    function refresh(){
    var logstr = "Log interval!";
    console.log( logstr );
    var feedback = $.ajax({//Ajax
                        type: "GET",
                        url: "mymodule/query/treerefresh",
                        async: false
                        }).responseText;//end of ajax
 
 
    $('edit-htmlstr').html(feedback).delay(10000).queue(function() {
            new refresh();
        });
    }
    //code ends
 
  }
};
})(jQuery);

  $items['mymodule/query/treerefresh'] = array(
    'page callback' => 'mymodule_query_tree_refresh',
    'access callback' => '...',
    'access arguments' => array( array( ... ) ),
    'file' => 'mymodule.inc',
    'type' => MENU_CALLBACK,
  );

function mymodule_query_tree_refresh() {
 
  $main_items = array();
  $main_names = array();
 
  // SQL ***
  $query = db_query('SELECT ...');
 
  foreach ($query as $record) {
      $main_items[] = $record->id;
      $main_names[$record->id] = $record->name;
    } // foreach
  // ******
 
 
  // html string for display
  $html = "<ul>";
 
  // recursive node tree
  foreach ( $main_items as $item ) {
     $html.= "<li>" . $main_names[$item];
     $html.= display_tree_node( $item );
     $html.= "</li>";
  }	// foreach
 
  $html.= "</ul>";
 
  print ( $html );
  return NULL;
}