diff --git a/src/pages/[platform]/build-ui/formbuilder/validations/index.mdx b/src/pages/[platform]/build-ui/formbuilder/validations/index.mdx
index 49ddec5045b..140a334c9aa 100644
--- a/src/pages/[platform]/build-ui/formbuilder/validations/index.mdx
+++ b/src/pages/[platform]/build-ui/formbuilder/validations/index.mdx
@@ -54,7 +54,7 @@ Every form provides an `onValidate` event handler to provide additional validati
   onValidate={{
     address: (value, validationResponse) => {
       const firstWord = value.split('')[0];
-      if (!isNaN(str)) {
+      if (!isNaN(firstWord)) {
         // check if the first word is a number
         return {
           hasError: true,