>For example, the element object is not implemented correctly on any 
>browser I have tried so far and I say any, and believe me I would love 
>to be proved wrong.

One of the more problematic markers in issue is also IFRAME in the old or
mobile browser.

However in theory HTML 4.01 it does not have impact on the old versions and
would have to be retrocompatible with the old browser (representing itself
at least like text)

Luca Mascaro