doctype helper default value was missing a "1".
diff --git a/system/helpers/html_helper.php b/system/helpers/html_helper.php
index e552b86..3117035 100644
--- a/system/helpers/html_helper.php
+++ b/system/helpers/html_helper.php
@@ -246,7 +246,7 @@
  */
 if ( ! function_exists('doctype'))
 {
-	function doctype($type = 'xhtml-strict')
+	function doctype($type = 'xhtml1-strict')
 	{
 		global $_doctypes;