So i think the consensus is that IE 6 and 7 (and 8?) do not support XHTML rendering. Only Firefox, maybe Chrome, and other browsers support it.
So the question is, why are we using XHTML DOCTYPE and those self-closing tags like <img /> when XHTML is not supported by IE 6 & 7 ? are we making a "hopeful" attempt? trying to make something that is a standard, but when 60% or 2/3 of the browsers in use are not supporting it?
For example, Facebook is using it. Even SitePoint's Forum pages are using it. Usually I just use HTML 4.01... but when writing Facebook pages, I sometimes will use XHTML format... as least if Facebook gets the content and parses it, it can understand XHTML and that's understandable... but Facebook is serving the content to general users again with a DOCTYPE of XHTML too... and even SitePoint or W3C.org is serving its pages to IE 7 with a DOCTYPE of XHTML. that's kind of weird, isn't it? thanks.