Rather, well-formedness refers to a low level of syntax (maybe better referred to as lexical correctness), while validity refers to a higher level of syntax (call it "structural" if you like).
Note: The Namespaces in XML Recommendation [XML Names] assigns a meaning to names containing colon characters.
For validation to be possible, the XML document needs to be associated to a DTD or an XML schema. Up until this point, this lesson has concentrated on the non-validating parser.
In fact, it took Larry Wall more than a couple of months just to add the Unicode support to Perl that XML assumed.uses the non-validating parser by default, but it can also activate validation.Activating validation allows the application to tell whether the XML document contains the right tags or whether those tags are in the right sequence.Client applications use method calls defined in the parser API to receive or request information the parser retrieves from the XML document.The parser shields the client application from all the complex and not particularly relevant details of XML including: One of the original goals of XML was that it be simple enough that a “Desperate Perl Hacker” (DPH) be able to write an XML parser.