[kronolith] better javascript date validation example

[Chuck Hagenbuch]

Quoting John Woodell <woodie at netpress.com>:

> I started with some of the javascript from the Kronolith event page,
> and made some tweeks to catch bad dates (you cannot select Feb 31, etc.)
>
> Should I try to roll these changes back into Kronolith?

Sure, patches against HEAD would be great!

-chuck

--
Charles Hagenbuch, <chuck at horde.org>
They're just looking at a wall of meat.