[dev] How do I use the JS-file caching mechanism of Horde?

[Sebastian Birnbach]

I am playing around with Horde_Views and the Javascript gems in /js, like
tables.js or form_sections.js. It is a real pity that there is so little
documentation (none at all?) on these.

Anyway, I am wondering how to include JS files making use of the Horde JS
caching system. For instance, I see in the HTML source of an average Horde
page something like

  <script type="text/javascript"
src="/js/prototype.js?v=596ca0a81b7fe741719c6df2f8b52a22

and I assume that the v=... is a caching key. What would be the proper way
to get such a key and denote inclusion of a JS file in a Horde_View with
caching support?