diff --git a/data/web/inc/ajax/sieve_validation.php b/data/web/inc/ajax/sieve_validation.php
index eb421b4a48..99be1f0c06 100644
--- a/data/web/inc/ajax/sieve_validation.php
+++ b/data/web/inc/ajax/sieve_validation.php
@@ -4,14 +4,14 @@
 if (!isset($_SESSION['mailcow_cc_role'])) {
   exit();
 }
-if (isset($_GET['script'])) {
+if (isset($_REQUEST['script'])) {
   $sieve = new Sieve\SieveParser();
   try {
-    if (empty($_GET['script'])) {
+    if (empty($_REQUEST['script'])) {
       echo json_encode(array('type' => 'danger', 'msg' => $lang['danger']['script_empty']));
       exit();
     }
-    $sieve->parse($_GET['script']);
+    $sieve->parse($_REQUEST['script']);
   }
   catch (Exception $e) {
     echo json_encode(array('type' => 'danger', 'msg' => $e->getMessage()));
diff --git a/data/web/js/site/mailbox.js b/data/web/js/site/mailbox.js
index af2862a37e..018233673a 100644
--- a/data/web/js/site/mailbox.js
+++ b/data/web/js/site/mailbox.js
@@ -179,9 +179,8 @@ $(document).ready(function() {
     // Get script_data textarea content from form the button was clicked in
     var script = $('textarea[name="script_data"]', $(this).parents('form:first')).val();
     $.ajax({
-      dataType: 'json',
       url: "/inc/ajax/sieve_validation.php",
-      type: "get",
+      type: "post",
       data: { script: script },
       complete: function(data) {
         var response = (data.responseText);