Drupal has adopted Ajax, review how it implemented in Forms
Drupal has adopted Ajax - full integration
Ajax is the process of dynamically updating parts of a page's HTML based on data from the server.
When a specified event takes place, a PHP callback is triggered, which performs server-side logic and may return updated markup or JavaScript commands to run.
After the return, the browser runs the JavaScript or updates the markup on the fly, with no full page refresh necessary.
Many different events can trigger Ajax responses, including Clicking a button, Pressing a key, Moving the mouse
Code Snippet
$response = new AjaxResponse();
$response->addCommand(new ReplaceCommand('#edit-date-format-suffix', '<small id="edit-date-format-suffix">' . $format . '</small>'));
return $response;'#ajax' => [
'callback' => 'Drupal\config_translation\FormElement\DateFormat::ajaxSample',
'event' => 'keyup',
'progress' => [ 'type' => 'throbber', 'message' => NULL, ],
],
