diff --git a/functions/api/webview-captcha.ts b/functions/api/webview-captcha.ts
index deac2e2..89e484d 100644
--- a/functions/api/webview-captcha.ts
+++ b/functions/api/webview-captcha.ts
@@ -11,13 +11,13 @@ export async function onRequestGet(context: RequestContext) {
         <script>
           function handleError(error) {
             console.error(error);
-            window.flutter_inappwebview.callHandler("onToken", null);
+            onToken.postMessage(null);
 
             return true;
           }
 
           function returnToken(token) {
-            window.flutter_inappwebview.callHandler("onToken", token);
+            onToken.postMessage(token);
           }
         </script>
       </body>