What Are Well-Formed XML Documents?

Definition: XML with correct syntax is well-formed XML. Parsers check XML documents for well-formedness. If a document is not well formed, the parser discontinues processing and returns an error message that indicates where the malformed syntax occurred. XML declaration is included, it must appear on the very first line.

An XML declaration looks like this: To date, the version attribute is always equal to “1.0,” although W3C issued a Candidate Recommendation of the XML 1.1 specification in October 2002 and expects to issue a finalized Recommendation in 2003. Other optional attributes of the XML declaration include the following: