diff --git a/verify-account-ui/script.js b/verify-account-ui/script.js
index 6df6bf0..740d101 100644
--- a/verify-account-ui/script.js
+++ b/verify-account-ui/script.js
@@ -4,11 +4,16 @@ codes[0].focus()
 
 codes.forEach((code, idx) => {
     code.addEventListener('keydown', (e) => {
-        if(e.key >= 0 && e.key <=9) {
+        if (e.key >= 0 && e.key <= 9) {
             codes[idx].value = ''
-            setTimeout(() => codes[idx + 1].focus(), 10)
-        } else if(e.key === 'Backspace') {
-            setTimeout(() => codes[idx - 1].focus(), 10)
+            if (idx !== codes.length - 1) {
+                setTimeout(() => codes[idx + 1].focus(), 10)
+            }
+        } else if (e.key === 'Backspace') {
+            if (!idx - 1 < 0) {
+                setTimeout(() => codes[idx - 1].focus(), 10)
+            }
+
         }
     })
-})
\ No newline at end of file
+})