Processing instructions are used to embed information intended for proprietary applications. The XML declaration is an example of a processing instruction. Processing instructions beginning with 'xml' or 'XML' have been reserved for standardization in the XML Version 1.0 specification and onwards.

<?PI-target ?>

where:

• PI_target: any name that does not contain the letters 'X' or 'x', 'M' or 'm', or 'L' or 'l' in that order.

<?xml version='1.0'?>
<?word document="test.doc" ?>
  <root>
  </root>

Rules:

• The string '?>' cannot be placed within a processing instruction, therefore, nested processing instructions are not allowed.

XML Guide TOC

XML Declaration
DOCTYPE Declaration & DTDs
ELEMENT Type Declaration
ATTLIST Declaration
ENTITY Declaration
NOTATION Declaration
CDATA Section
Processing Instruction
Conditional Section
Comments

Glossary