Writing XSLT IS programming, just like writing SQL or Prolog or Haskel is. You don't need to have to write

step 1. do this
step 2. do that
step 3. while something is true repeat step 4.
step 4. do whatever
step 5. blah blah

to be programming!

And that page ... without JavaScript? Really? Did you look at the sources? <script type="text/javascript" language="javascript" src="tooltip/script.js"></script> is what?

If you are used to "the industry standard" ... that is to something designed for the lowest common denominator of programming languages still in use today ... by all means go with XML::LibXML.