It is possible to do anti-aliased rounded corners with JQuery as well. A relatively simple solution, but just like all JS, it won't work unless JS is enabled. Nevertheless, it works nicely and is packed just below 10kb.
Search Google for "Blue Anvil Journal Anti-aliased Rounded Corners" and the first result should be a link to the post of the packed version of it. Then all you'll need is JQuery to get it to work. Use the packed version of that as well. jquery[dot]com