diff --git a/docs/demo.html b/docs/demo.html
index 4181e077..e1c4f6dd 100644
--- a/docs/demo.html
+++ b/docs/demo.html
@@ -1,4 +1,5 @@
-<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<!doctype html>
+<html lang="en">
 <head>
 	<title>Marked Demo Page</title>
 	<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7/jquery.min.js"></script>
