Hide a DIV via click and make another one visible instead via JavaScript?
===

ok, it's hard to tell (sorry for my broken english)...
i want to create a custom preview-image to my embedded media (you-tube and stuff)...

here's how i think it could work:

1. i have a DIV with a preview-image of a video and a custom play-button
2. right after click on that image/button the DIV hides and...
3. ...another DIV appears instead of that with the original iframe-embed-code
4. the video starts automatically

here's a little example (but i don't know how exactly that was done.. via fancybox?):
http://www.crackajack.de/2012/07/25/the-mayor-of-london-introduces-the-olympic-games/

any ideas how i could do that "easily"?

thanks alot!