The next two pages show the new no-JavaScript display in 2.3,
and its former rendering in 2.2.  2.3 now officially requires 
JavaScript for viewer pages, so this is largely a moot point.

In more detail, though, 2.3 removed the former HREF fallbacks 
on Prev, Next, and Index toolbar buttons, because they invoked 
URL popups that are now redundant with tooltips, and are arguably
more intrusive.  This makes these buttons unusable unless 
JavaScript is enabled, but viewer pages were already mostly 
unusable without JS in 2.2 anyhow (as is most of the web).