Sorry, but you’re mistaken. The parent never brought up IE - he was referring to the fact that when serving XHTML with the correct mime-type (application/xhtml+xml), any error causes the page not to render at all. This behaviour is intended per spec and was the same across all browsers, not due to lack of support. It’s called “draconian error handling”, consequence of being XML, and was a major factor in the death of XHTML.