It does:

- password metrics (tells you if its a strong password or not)

- submit lockout (user won’t be able to submit form until everything is good)

- minimum strength requirements (user needs to have a password of X strength)

Here is a demo of the script: http://www.thecreativeoutfit.com/freebies/passroids

You can view the options and download it here: http://www.thecreativeoutfit.com/index.php?view=jQuery-Password-Plugin