XML Syntax Notes
case-sensitive
well-formedness constraints (partial list)
every element must have start tag and end tag
elements must be correctly nested
attribute values must be quoted (matching single or
double)
XML parser checks XML document to make sure
that [1] it is well-formed (complies with all w.f.
constraints in specification), and [2] it is valid,
meaning the tag names and order conform to the
XML application’s Document Type Definition
(DTD)—the definition of what tags it may have and
in what order