[SOLVED] how to get a url to the /lib directory

Can anyone suggest the canonical way in a template to include a javascript file file under the /lib directory? I'm guessing it should be {g->url ....} but I'm a bit stumped what might come next.

By the way, if anyone can explain here what the {g->url...} object is - which php object it refers to - I'm happy to research and write up a page of docs on how to use it.

And the answer is....

{g->url href="lib/myjavascriptfolder/mywhatsit.js"}