YUI does CSS based transitions[1] and it falls back to a JavaScript implementation when the browser doesn't support them. [1] http://yuilibrary.com/yui/docs/tr

YUI does CSS based transitions[1] and it falls back to a JavaScript implementation when the browser doesn't support them. [1] http://yuilibrary.com/yui/docs/transition/ http://yuilibrary.com/yui/docs/transition/