diff --git a/ch18/bouncing-ball/script.js b/ch18/bouncing-ball/script.js
index 82dd4eb..2db4d08 100644
--- a/ch18/bouncing-ball/script.js
+++ b/ch18/bouncing-ball/script.js
@@ -19,6 +19,7 @@ function rotateAnimation(id, speed) {
 //once start button is clicked, call the rotate animation
 //and also enable the stop button
 document.getElementById('start').addEventListener('click', start);
+document.getElementById('stop').addEventListener('click', stop);
 
 
 function start() {
@@ -47,4 +48,4 @@ function start() {
         
     }
     
-}
+}
\ No newline at end of file