It's simple to build a web theme for johnCMS with auto detect user agent (no need sql)
here is the syntax
<?
-------
if(stristr($_SERVER['HTTP_USER_AGENT'],'windows') || stristr($_SERVER['HTTP_USER_AGENT'],'linux') ||
stristr($_SERVER['HTTP_USER_AGENT'],'macintosh') || stristr($_SERVER['HTTP_USER_AGENT'],'unix') ||
stristr($_SERVER[