XML Schema Validator

Location:	http://web.oesterchat.com/2011/07/
Redirect:
Well-formed:	True
Valid:	False
HTTP status code:	200 OK
HTTP Content Type:	text/html; charset=UTF-8
HTTP encoding:	utf-8
XML encoding:	utf-8
Used encoding:	utf-8
Public Identifier:	-//W3C//DTD XHTML 1.1//EN
System Identifier:	http://www.w3.org/TR/xhtml1/DTD/xhtml11.dtd
Validated as:	XHTML 1.1

You should specify the same value for the 'lang' and 'xml:lang' attributes. (2:2)
```
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de">
 ^
```

The 'aria-current' attribute is not declared. (228:51)

 <li><a href='http://web.oesterchat.com/2011/07/' aria-current="page">Juli 2011</a></li>
                                                  ^

If you think the validation result is incorrect or if you have difficulties to understand the messages, feel free to write me an e-mail.