main.js: a bit more sane code

templates/page.html

@@ -3,7 +3,7 @@
 <head>
 	<meta charset="utf-8">
 	<script type="text/javascript">
-		active_page = "page";
+		var active_page = "page";
 	</script>
 	{% include 'header.html' %}
 	<title>{{ title }}</title>