I'm wondering if there is a way I can animate a button when it is pressed (NOT rolled over) using HTML5/javascript?
I want to create an almost cartoonish button that expands a little when pressed and sparkles. I know that sounds kinda gawdy but I think the final result would look better than it sounds.
My inspiration is the ? blocks in the new Super Mario Brothers games.
What you are looking for is created by CSS3, not HTML5.
Here's a blog post with links to ten different tutorials on making all sorts of cool buttons with CSS3: http://www.catswhocode.com/blog/top-10-css3-buttons-tutorials.
Many of the buttons expand and stuff when rolled over by using the :hover selector. If you want a style to be applied when pressed, just substitute the :active selector instead.
Hope this gets you started.