XML Processing Instruction
An XML processing instruction passes application-directed instructions as <?target data?>, e.g., <?xml-stylesheet?> to associate a stylesheet.
Purpose
To embed instructions for specific applications inside an XML document, directing processing without affecting the document data.
Mechanism
The form <?target data?>: target identifies the application the instruction is for, and data is the instruction content (not XML-structured). The parser hands the PI to the application. The <?xml ...?> declaration is a special PI.
Use cases
- Associating XML stylesheets
- The XML declaration
- Application-specific directives