[Bug 15831] New: validator prevents XHTML5 from containing XML declaration

https://www.w3.org/Bugs/Public/show_bug.cgi?id=15831

           Summary: validator prevents XHTML5 from containing XML
                    declaration
           Product: Validator
           Version: HEAD
          Platform: PC
        OS/Version: Windows NT
            Status: NEW
          Severity: normal
          Priority: P2
         Component: HTML5
        AssignedTo: mike+validator@w3.org
        ReportedBy: garret@globalmentor.com
         QAContact: www-validator-cvs@w3.org


Created attachment 1074
  --> https://www.w3.org/Bugs/Public/attachment.cgi?id=1074
Start of an essay I wrote years ago, illustrating this XHTML5 validation issue.

I have a file reflection.html that is an XHTML5 file. Accordingly, I have an
XML header:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
...

The validator screams:

Line 1, Column 2: Saw <?. Probable cause: Attempt to use an XML processing
instruction in HTML. (XML processing instructions are not supported in HTML.)

As I understand, HTML5 allows representation in a true application/xhtml+xml
file. The http://validator.nu/ validator validates this file just fine (if I
select "XHTML5".

(The W3C validator doesn't have an "XHTML5" option. What's crazy about this
situation is that the whole point of an XML declaration is to indicate that the
file is XML. Therefore, if I choose "HTML5" and the validator sees an XML
declaration, is it really a leap to think that maybe I'm validating an XHTML5
file?" Or maybe if it sees an XML declaration and then a "<!DOCTYPE html>", it
would just know I'm validating an XHTML5 file? Isn't that the whole reason we
have an XML declaration and a DOCTYPE declaration?)

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Received on Wednesday, 1 February 2012 16:50:10 UTC