Hi Valdis, it seems in the StyleSheetExtensions / JavaScriptExtensions only the "basic" variables are defined, like $doc, $request or $xcontext The $isGuest is a "derived" variable; you can find the definition in /templates/xwikivars.vm I am not sure if there is a better way, but at least you can get the code working by copy & paste the definition for the variables you need from the xwikivars.vm to the corresponding objects hope this helps, Clemens

Thanks Clemens and Marius! I updated http://platform.xwiki.org/xwiki/bin/view/DevGuide/SkinExtensionsTutorial#HH… with additional notes. Valdis

One thing to keep in mind: client (browser) caches don't know about Velocity. This means that if you write different CSS rules depending on some variables, like is guest or authenticated users, then when a user opens the wiki and authenticates, something "strange" will happen. The browser will first fetch the CSS file, which will contain the rules for the guest user. This CSS is stored in the browser's cache, and it won't be re-fetched unless the user forces a cache refresh. So after loggin in, the user will continue to see the guest UI. This means that a feature intended for improving the performance now breaks your intended behavior. One solution is to disable caches (which is possible for skin extensions, but not for filesystem files), but this impacts the performance. Another solution is to put different parameters in the URL used to fetch the CSS or JS, for example: $xwiki.ssx.use('Some.Document', {'isGuest': $isGuest}) $xwiki.jsx.use('Some.Document', {'user': $xcontext.userReference, 'hasAdmin': $hasAdmin}) Yet another solution (which only works for JS, not for CSS) is to store the variable data in the HTML, and the JS will fetch it from there. There are already plenty of variables stored in <meta> elements, such as the current document coordinates and the CSRF prevention token, and some are defined as JS variables, such as XWiki.hasEdit. This is the preferred way of passing information to JS scripts, since it allows the extensions to be cached, while still being aware of the current context. The downside is that the <meta> fields can't be easily altered from the document content, they have to be modified in a skin file or in the global administration (there's a special field for modifying the metadata). On Thu, Aug 22, 2013 at 10:22 AM, Marius Dumitru Florea < mariusdumitru.florea(a)xwiki.com&gt; wrote: