Added on_submit parameter that receives a callback with one parameter to access the submitted data.

module.php

@@ -9,6 +9,7 @@ return new class extends Module
     const OPTIONS_ELEMENT = 'element';
     const OPTIONS_LABEL = 'label';
     const OPTIONS_DATA = 'data';
+    const OPTIONS_CALLBACK_ON_SUBMIT = 'on_submit';
 
     // element specific
     const OPTIONS_SHOW_PLACEHOLDER = 'show_placeholder';
@@ -167,18 +168,18 @@ return new class extends Module
         return count($this->collectFormKeys()) > 0;
     }
 
-    public function getData()
+    private function extractData()
     {
         if (!$this->isSubmitted()) {
             return [];
         }
-        $data = [];
+        $extracted_data = [];
         $keys = $this->collectFormKeys();
         sort($keys, SORT_NUMERIC);
         foreach ($keys as $key) {
-            $data [] = $_POST[$key];
+            $extracted_data [] = $_POST[$key];
         }
-        return $data;
+        return $extracted_data;
     }
 
     private function processAction($action)
@@ -201,7 +202,20 @@ return new class extends Module
         // add default options
         $options += [
             self::OPTIONS_DATA => [],
+            self::OPTIONS_CALLBACK_ON_SUBMIT => function ($data) {
+                return true;
+            },
         ];
+
+        // extract data that has been submitted
+        $submitted_data = $this->extractData();
+        if (// there is data that has been submitted, and callback returns false, stop module
+            !empty($submitted_data)
+            && !$options[self::OPTIONS_CALLBACK_ON_SUBMIT]($submitted_data)
+        ) {
+            return false;
+        }
+
         // SETUP FORM ATTRIBUTES
         $this->setAttribute('method', $options[self::OPTIONS_METHOD] ?? 'POST');
         $this->setAttribute(