Website "build" animations... how are they done in non-Flash sites?

Hi all,

I’ve been working in Flash for years and have only recently gone back to development in HTML/CSS. I’ve seen several amazing sites out there that have animation builds when the site or page first loads that seem to be done in CSS or maybe Javascript. I would be able to easily do this in Flash but I don’t have a clue in HTML/CSS… How is this done?

Here’s an excellent example:
http://www.quazarwebdesign.com/

See how the page elements animate into place when it first loads? If anyone can explain that to me so I can start learning how to do it in my projects, I’d really appreciate it!

Thanks!