Doc Type Definition: A Syntax Question

Question

In the top of my webpages it days:

<!doctype html><html xmlns="http://www.w3.org/1999/xhtml" lang="nl" xml:lang="nl">

Q1:
Which one is more fault-proof/better in your opinion: <!doctype html> or <!doctype html/>

Q2:
I wonder whether there is anything shorter than this, which will define the language:
<html xmlns="http://www.w3.org/1999/xhtml" lang="de" xml:lang="de">

And should that be ending with > of />?

Thanks very much.

Konrad Rudolph · Accepted Answer · 2011-02-16 15:55:53Z

2

Q1: This is very simple: <!doctype html/> is wrong. The doctype is not a self-closing tag, neither in HTML nor in XML. The only valid declaration for HTML5 is therefore <!doctype html>.

Q2: That depends. You don’t actually need to declare the XML namespace if you’re using HTML rather than the XHTML variant (and the xml:lang attribute would also be pointless). In that case, the doctype (see Q1) is entirely sufficient:

<!doctype html>
<html lang="nl">
    …
</html>

On the other hand, if you want to use XHTML then you should add the XML namespace (and, yes, the xml:lang attribute). Using XHTML does have advantages, primarily because some editors/evaluators will treat errors stricter and can thus provide better diagnostics for errors.

edited Feb 16, 2011 at 15:55

answered Feb 16, 2011 at 15:43

Konrad Rudolph

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6 Comments

Quentin Over a year ago

Likewise, if you're not using XML, then having the additional namespaced xml:lang attribute is pointless.

Konrad Rudolph Over a year ago

@David: That goes without saying. Or perhaps not. ;-) I’ll add it.

Quentin Over a year ago

I wouldn't call the document language an added bonus. Making sure that screen readers get the right pronunciation database and that search engines file the document under the right language is a basic essential in my book. It is just the xml: variant that is pointless.

Sam Over a year ago

+1 very clear! Thanks all! Updated the question, see the '>' or '/>' on the second part pelase.

Quentin Over a year ago

<html lang="de">, and no, only elements with no content can have a / and that is useless, optional syntactic sugar if you are writing HTML (rather than XML).

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