diff --git a/docs/index.html b/docs/index.html
index 787e607..c3bbf2b 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -20,7 +20,13 @@
     <label for="name">Name : </label><input id="name" value="World">
     <button onclick="hello()">Hello</button>
     <script>
-      navigator.serviceWorker.register('sw.js')
+      (async () => {
+        try {
+          await navigator.serviceWorker.register('sw.js')
+        } catch (e) {
+          console.error(e)
+        }
+      })()
     </script>
   </body>
 </html>
\ No newline at end of file