First, ESS is not a standard. It does allow for standard CSS attributes, plus “extended” attributes that affect the behavior of an Element. Thus, I called it an “extended” stylesheet; but I am open to suggestions.

To Ross’s point about having two points of abstraction, this is a concern. That is why I designed it to support CSS as well, so that they could both in a single file. That said, I am also intrigued by the idea that the “paint” (CSS) and the “wiring” (ESS) are really two different things and are perhaps better off in two different places.

Finally, I will continue to introduce more interesting examples. This one was intentionally brain-dead to make it clear what ESS actually does. I myself am interested to see how this is applied. I have my own ideas, but don’t have firm opinions on “best practices” yet. To Daniel’s point, I do think that ESS should be limited to mapping behaviors that are essentially stylistic, like :hover is for anchors.

I really like the example. I just don’t like the connector’s sitting in a CSS file. Like Ross says, a bit messy.

However, there is a difference between having unused css classes attached to elements, and to ess which is sudo css with javascript mixed in. It seems to complicate the behaviour model by having two points of abstraction and seems dirty to me!

I look forward to seeing more uses of this library to see it used as it was designed to be (the example is too basic for me – it seems it would be achieved just as cleanly with the original behaviour rules)