webkit-transition for "top" and "bottom" properties

Question

I'd like to make a css animation where a div (centered on a screen using top and bottom properties) expands by setting top and bottom to 20px.

Is it possible? When I try to make it happen with:

-webkit-transition-property: top, bottom;
-webkit-transition-duration: 0.5s;

animation is not performed. Am I doing something wrong, or is it not supposed to work with these properties?

P.S. I'm doing this for a Titanium desktop application, so only webkit matters...

Answer 1

Here's some code that works on Chrome v31:

-webkit-transition: top 0.5s, bottom 0.5s;