Why did it not work? I have no idea!

html_playground/index.html

@@ -20,7 +20,7 @@ <h1>HTML Playground</h1>
 <script>
     document.getElementById('run').onclick = () => {
         document.getElementById("output").innerHTML = document.getElementById("code").value;
-    }
+    } // why was there random characters here
 </script>
 </head>
 </html>