Animations not running smooth

My animations no matter how big or small when published and veiwed through my broswer, seem a little choppy. Not by much but they just don’t run as smooth as they seem to in flash. I always biuld a preloader for all my animations and run in 30fps but something even as small as a a bar fill wont run in my broswer window like it does in flash.

Is there something Im overlooking?

Thanks for any help.