[throwaway1980]

What I meant was, why don't browser implementors balk at it?

[jeffasinger]

I think the thing is, that JS can be executed separately from the layout engine, but CSS can't, however, I'm definitely not an expert in the matter.

[gcr]

Browser vendors control the javascript VM. Though we can't solve the halting problem, we can just throttle or unplug the JS interpreter if it causes usability problems.

But CSS is required for the site to look right There's no way to turn it off without messing with the site's layout.