Certain crawlers may execute js but the vast majority don't. they typically don't post forms either, just follow links.
I would rewrite it so that the delete function POSTs instead of GETs. in fact i always require that the delete actions be called via a POST such that if you try to use a simple GET request you'll get a 404.
In any case, the example was a very nice demo of ajax, you should take it at face value and use it for your own needs.
Could i just ask, tho, why people prefer jQuery to prototype?