Javascript: pseudo-protocol in admin tree block is bad

href="javascript: ..." is not a standardised protocol, and does not degrade gracefully with Javascript disabled, see:
http://diveintoaccessibility.org/day_13_using_real_links.html
http://lists.evolt.org/archive/Week-of-Mon-20041206/166888.html

I'm about to commit this patch which uses <a href="#" onclick="...; return false"> – Return false is important - see here,
http://cs.wellesley.edu/~cs110/examples/return.html

Note, href="#" isn't ideal but it's an improvement!