1.3.x isXMLDoc() says XHTML+XML is XML -- right?

1.3.x isXMLDoc() says XHTML+XML is XML -- right?


Re this ticket:
http://dev.jquery.com/ticket/4283
Version 1.3.x now detect documents served as XHTML+XML to be XML
documents. This means the attributes-are-sometimes-properties magic
doesn't happen in jQuery.attr. So,
$("#check").attr("checked", true);
sets an attribute named "checked" on #check but does not set the
checked property/expando.