[ off topic - how to ]

> It adds a new query string to the url (site.com/page.html#top)
> The JS method puts less strain on the server since it doesn't have to 
> send a new query to the server to find out where on the page to jump to.

A proper implementation of fragment only URLs should not invoke the 
server at all.  The real problem with this is that it pollutes the
history stack, which is why I can seem some advantage in the scripting,
but done properly, with onclick and an href fallback.

However, in my exerience, with the exception of those on mobile phones
all browser have home key support, so this function is redundant, anyway.