first commit

media/com_languages/js/admin-language-edit-change-flag.js

@@ -0,0 +1,20 @@
+/**
+ * @copyright  (C) 2018 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+document.addEventListener('DOMContentLoaded', () => {
+  document.getElementById('jform_image').addEventListener('change', ({
+    currentTarget
+  }) => {
+    const flagSelectedValue = currentTarget.value;
+    const flagimage = document.getElementById('flag').querySelector('img');
+    const src = `${Joomla.getOptions('system.paths').rootFull}/media/mod_languages/images/${flagSelectedValue}.gif`;
+    if (flagSelectedValue) {
+      flagimage.setAttribute('src', src);
+      flagimage.setAttribute('alt', flagSelectedValue);
+    } else {
+      flagimage.removeAttribute('src');
+      flagimage.setAttribute('alt', '');
+    }
+  }, false);
+});