[html5] XHTML5 validator: Polyglot: works as both HTML and XHTML

Wed Jul 7 09:45:34 PDT 2010

On the page at http://validator.nu/, I'm not sure what this setting is
supposed to do. When I give the validator the following HTML:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Test Page</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>

<body>
<p>
First paragraph
<p>
another paragraph
</p>
</body>
</html>

The validator reports no errors, but the document is not really
polyglot, as the first opening <p> has no closing </p>.

My goal is to check to see that I have an HTML document that follows
all the XML rules for opening/closing tags, so that I can use XML
tools on the document at some later point.