Yes, that's the correct CSS way. Besides, this plugin does not work with box-sizing border-box. Which is unacceptable at (almost) 2013. But if in need to do th

Yes, that's the correct CSS way. Besides, this plugin does not work with box-sizing border-box. Which is unacceptable at (almost) 2013. But if in need to do this kind of things with Javascript, please take a look at https://github.com/atirip/jquery.pp https://github.com/atirip/jquery.pp This repo is not solely of dimensions, but you will find many useful and normalized (all your tags may even be mixed of content-box and border-box) dimension methods inside, both to measure and to set dimensions.