jQuery Validator method for passwords regex from http://forums.phpfreaks.com/topic/273119-yet-another-password-regex/?p=1405494

jquery.validator.password.js

/**
 * Password regex
 * ^           # Bind the RegExp to the beginning of the string.
 * (?=.{8,})   # Followed by 8 or more characters (min length)
 * (?=.*\d)    # At least one digit.
 * (?=.*[a-z]) # At least one lower-case character.
 * (?=.*[A-Z]) # At least one upper-case character.
 * .*\z        # Followed by any number of characters, before the end of the string.
 */

jQuery.validator.addMethod("password", function(value, element) {
    return this.optional(element) || /^(?=.{8,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).*$/.test(value);
}, "Invalid password format. You must use at least 8 characters. Your password must contain uppercase and lowercase letters and digits.");