In the past, elseif was used within templates. Now, you've mixed up the
usage of else if and elseif.
{if JQUERY_SOURCE == 'google'}
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.2/jquery-ui.min.js"></script>
-{else if JQUERY_SOURCE == 'microsoft'}
+{elseif JQUERY_SOURCE == 'microsoft'}
<script type="text/javascript" src="//ajax.aspnetcdn.com/ajax/jQuery/jquery-2.0.0.min.js"></script>
<script type="text/javascript" src="//ajax.aspnetcdn.com/ajax/jquery.ui/1.10.2/jquery-ui.min.js"></script>
{else}