made table of content in wiki accessible via keyboard enter key

resources/assets/javascripts/bootstrap/studip_helper_attributes.js

@@ -227,3 +227,12 @@ $(document).on('change', 'input[data-must-equal]', function() {
         this.setCustomValidity('');
     }
 });
+
+//Generalisation: The enter-accessible class allows an element to be accessible via keyboard
+//by triggering the click event when the enter key is pressed.
+$(document).on('keydown', '.enter-accessible', function(event) {
+    if (event.code == 'Enter') {
+        //The enter key has been pressed.
+        $(this).trigger('click');
+    }
+});

templates/contentbar/contentbar.php

@@ -16,7 +16,7 @@
         <div class="contentbar-icons">
             <? if ($toc->hasChildren()) : ?>
                 <input type="checkbox" id="cb-toc">
-                <label for="cb-toc" class="check-box" title="<?= _('Inhaltsverzeichnis') ?>" >
+                <label for="cb-toc" class="check-box enter-accessible" title="<?= _('Inhaltsverzeichnis') ?>" tabindex="0">
                     <?= Icon::create('table-of-contents')->asImg(24) ?>
                 </label>
                 <?= $ttpl->render() ?>

templates/toc/generic-toc-list.php

@@ -2,7 +2,7 @@
 <article class="toc_overview toc_transform" id="toc">
     <header id="toc_header">
         <h1 id="toc_h1"><?= sprintf(_('Inhalt (%u Elemente)'), htmlReady($root->countAllChildren())) ?></h1>
-        <label for="cb-toc" class="check-box" title="<?= _('Schließen')?>">
+        <label for="cb-toc" class="check-box enter-accessible" title="<?= _('Schließen')?>" tabindex="0">
             <?= Icon::create('decline')->asImg(24) ?>
         </label>
     </header>