     |
Usage:
Allow documents to contain instructions for applications.
Notation
<?xml-stylesheet type="text/xml" href="#style1"?>
PI's have to start with a target (xml-stylesheet)
'XML' or 'xml' cannot be used as a PI target.
Avoid Usage:
Support for PIs have not been uniform, they are stripped from SOAP messages, and there is no XML Schema support for them. Use element and attribute markup instead.