diff --git a/example1/index.html b/example1/index.html
index 8932986..f891707 100644
--- a/example1/index.html
+++ b/example1/index.html
@@ -1,7 +1,9 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
     <meta charset="utf-8">
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
     <title></title>
   </head>
   <body>
