[Javascript] detecting CSS capability

[Paul Novitski]

Friends,

I'm wondering about the various ways it might be possible to detect whether 
CSS is functional within a browser, and how dependable any of those checks 
might be.

Such tests, of course, would not check for the presence of inline styles or 
a stylesheet link in html, but rather would attempt to determine whether 
the browser is cognizant of them or acts on them.  Here's what I've come up 
with so far:

A browser might be CSS-enabled if any of the following are true:

- if the collection document.styleSheets exists in the DOM

- If any DOM object has the 'style' property

- If any DOM object has the 'currentStyle' property

- If any DOM object has the 'runtimeStyle' property

It *might* be possible to detect whether any object has been modified by 
CSS, although my experiments haven't revealed the way.  CSS affects 
presentation, not object content, and client-side scripts appear not to be 
aware of the presentation of objects (except through their style 
settings).  CSS cannot remove or add objects to the DOM for javascript to 
detect.

CSS2 does include the :before and :after pseudo-elements which appear to 
insert content, but again this content is purely visual presentation and 
does not change the innerText or innerHTML of objects to which it is applied.

Any suggestions?

Thanks,
Paul