1 files changed, 23 insertions, 0 deletions
diff --git a/core/misc/jquery.tabbable.shim.es6.js b/core/misc/jquery.tabbable.shim.es6.js
new file mode 100644
index 000000000000..381355f2d665
--- /dev/null
+++ b/core/misc/jquery.tabbable.shim.es6.js
@@ -0,0 +1,23 @@
+/**
+ * @file
+ * Defines a backwards-compatible shim for the jQuery UI :tabbable selector.
+ */
+
+(($, Drupal, { isTabbable }) => {
+  $.extend($.expr[':'], {
+    tabbable(element) {
+      // The tabbable library considers the summary element tabbable, and also
+      // considers a details element without a summary tabbable. The jQuery UI
+      // :tabbable selector does not. This is due to those element types being
+      // inert in IE/Edge.
+      // @see https://allyjs.io/data-tables/focusable.html
+      if (element.tagName === 'SUMMARY' || element.tagName === 'DETAILS') {
+        const tabIndex = element.getAttribute('tabIndex');
+        if (tabIndex === null || tabIndex < 0) {
+          return false;
+        }
+      }
+      return isTabbable(element);
+    },
+  });
+})(jQuery, Drupal, window.tabbable);