XHTML A demo of Draconian error handling of XHTML 1.0 in the browser: nfreear.github.io/xhtml Further Reading How Did We Get Here? in Dive Into HTML5, by Mark Pilgrim, book (2010) Postel's Law, by Mark Pilgrim (2004) Robustness Principle, in RFC 761, by Jon Postel (1980) Servor supports XHTML Content-Type (2020)