One thing XHTML(2) does not provide is resilience to invalid code, which is
very important for sites featuring third-party content like advertisements,
or user-generated content like blogs. Script-only add-ons like database
access and Web sockets in HTML5 are a big advantage for Web applications
Per Ian Hickson's request, first of my notes on the current HTML 5 draft
Section 1.6.3, where you compare HTML5 with XHTML2 and XForms, you write
However, XHTML2 and XForms lack features to express the semantics of
many of the non-document types of content often seen on the Web. For
instance,
