According to the W3C, there should technically be no difference in the handling of XML or HTML/SGML between the different ways to input it. Thus, anything that you can specify in the DOM (some things are read only, though, and can't be specified by the DOM) should be handled exactly the same as if it was part of the original document source sent from the server. However, there is nothing that indicates to the parser that a style or script tag should be parsed through a parser for their respective content languages, and thus some implementations may behave differently when you use the DOM and when you include it in the original document source (they use native host parsing for the latter, but only DOM/XML/HTML for the former) - iew's not sending some form fields that are created by the DOM is a good example, though that is a bug, not a difference in features as for example the fact that op7 can't load external scripts dynamically is (both Opera and Apple tell us that they are working on this, however. They just don't have dynamical reparsing for these types objects yet).
Hmm, about that bug filing, I can do it if you wish. I've just created a testcase: <http://liorean.web-graphics.com/bugr...edobjects.html
Iew has the interessting notion that the DOM should have no property access to the other language parsed nodes...