Farewell, XML declaration

Martin Kliehm — Wed, 04 Jun 2008 16:00:04 +0000

For years I have been using an XML declaration prior to my DOCTYPE declaration:

TR/xhtml1/DTD/ xhtml1-strict.dtd">

It was obvious for me that such a declaration would be a good thing to have since XHTML is XML after all. Only later I learned that it triggers a bug in IE6 to render pages in quirks mode with a broken box model. But I was used to build workarounds for Internet Explorer bugs since IE 3.0 and never knew anything but the broken box model in IE, so I continued to use the declaration.

Until recently my colleague Thomas Junghans took the trouble to research, and found this phrase in the XHTML specification:

An XML declaration is not required in all XML documents; however XHTML document authors are strongly encouraged to use XML declarations in all their documents. Such a declaration is required when the character encoding of the document is other than the default UTF-8 or UTF-16 and no encoding was determined by a higher-level protocol.

The declaration is not required as long as you encode in UTF-8 or UTF-16, you are only strongly encouraged to use it. Gasp!

Richard Ishida lists some advantages of using the declaration when serving the pages with an XML MIME type or viewing them offline, however I’m convinced the disadvantages prevail.

So as long we are stuck with IE6 — and people say that could be as long as 2014 when support for Windows XP ends (reminder to self: throw a party on 8 April, 2014) — I will refrain from using the XML declaration. Amen.

Learning the World » 2014

Farewell, XML declaration