diff --git a/Practice/03_09/script.js b/Practice/03_09/script.js
index 1dd07f08..38b85aa4 100755
--- a/Practice/03_09/script.js
+++ b/Practice/03_09/script.js
@@ -16,6 +16,7 @@ const backpack = {
     left: 26,
     right: 26,
   },
+  lidOpen: false,
   toggleLid: function (lidStatus) {
     this.lidOpen = lidStatus;
   },