Howdy; Finally getting around to tweaking some html snippets, and I'm stuck -

this is what I have: <li id="${1}"><a href="#">$1</a></li>$2

what I'm trying to accomplish is (replacing the spaces with underscores and making it all lowercase) <li id="this_is_a_mixed_case_string_with_spaces"><a href="#">This is a Mixed case String with SPACES</a></li>

I'd really like to understand how to accomplish this (rather than just get an answer).

thanks in advance

saul