diff --git a/public/index.php b/public/index.php
index 29784fd..8a78544 100644
--- a/public/index.php
+++ b/public/index.php
@@ -262,7 +262,7 @@ if (isset($_GET["embed"])) {
     ?>
     <script nonce="<?php echo $SECURE_NONCE; ?>">
         window.addEventListener("load", function () {
-            window.postMessage(document.documentElement.scrollHeight + "px", "*");
+            parent.window.postMessage(document.documentElement.scrollHeight + "px", "*");
         });
     </script>
     <?php