refs #20375 [finc] set focus on hierarchy tab

* define hierarchy tree tab as ajax-loadable
* fix: set aria-controls for ajax tabs just-in-time to avoid reference of aria to unloaded tab-content, also #19938

module/finc/src/finc/RecordTab/HierarchyTree.php

@@ -67,4 +67,15 @@ class HierarchyTree extends \VuFind\RecordTab\HierarchyTree
         }
         return false;
     }
+
+    /**
+     * Can this tab be loaded via AJAX?
+     *
+     * @return bool
+     */
+    public function supportsAjax()
+    {
+        // No, special width adjustment needed.
+        return true;
+    }
 }

themes/finc-accessibility/js/record.js

@@ -274,6 +274,8 @@ function recordDocReady() {
 
     // accessibility: mark tab controls as selected
     $top.find('.record-tab.active').find('a').attr('aria-selected', 'false');
+    // accessibility: set information about connection between tab control and tab content
+    $(this).attr('aria-controls', tabid);
     $('#' + tabid + '-tabselector').attr('aria-selected', 'true').attr('aria-controls', tabid);
 
     // accessibility: set aria-hidden for content panes

themes/finc/templates/record/view.phtml

@@ -71,7 +71,7 @@
                   <a href="<?= $this->recordLink()->getTabUrl($this->driver, $tab) ?>#tabnav"
                     <?php if ($obj->supportsAjax() && in_array($tab, $this->backgroundTabs)): ?> data-background<?php endif ?>
                      aria-selected="<?= $isActiveTab ? "true" : "false" ?>"
-                     aria-controls="<?= $tabName ?>"
+                     <?php if($isActiveTab): ?>aria-controls="<?= $tabName ?>"<?php endif; ?>
                      id="<?= $tabName ?>-tabselector">
                     <?= $this->transEsc($desc) ?>
                     <span class="sr-only load-tab-content"><?= $this->transEsc('load_tab_content_hint') ?></span></a>