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Processing Instruction
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<h2 id="syntax">Syntax</h2> <p>An SGML processing instruction is enclosed within <? and >.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> </p><p>An XML processing instruction is enclosed within <? and ?>, and contains a <i>target</i> and optionally some content, which is the node value, that cannot contain the sequence ?>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> </p> <?PITarget PIContent?> <p>The <a href="/facts/XHTML/6qHnmJSg">XML Declaration</a> at the beginning of an XML document (shown below) is another example of a processing instruction,<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> however it may not technically be considered one.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> </p> <?xml version="1.0" encoding="UTF-8" ?> <h2 id="examples">Examples</h2> <p>The most common use of a processing instruction is to request the XML document be rendered using a <a href="/facts/Extensible_Stylesheet_Language/fzT8tD7u">stylesheet</a> using the 'xml-stylesheet' target, which was standardized in 1999.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> It can be used for both <a href="/facts/XSLT/0gw4WVyJ">XSLT</a> and <a href="/facts/Cascading_Style_Sheet/tA90XBQo">CSS</a> stylesheets. </p> <?xml-stylesheet type="text/xsl" href="style.xsl"?> <?xml-stylesheet type="text/css" href="style.css"?> <p>The <a href="/facts/DocBook/8RpRVfCQ">DocBook</a> XSLT stylesheets understand a number of processing instructions to override the default behaviour.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p><p>A draft specification for <a href="/facts/Robots_exclusion_standard/VhGtVKEG">Robots exclusion standard</a> rules inside XML documents uses processing instructions.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p> <h2 id="external-links">External links</h2> <ul><li><a href="http://www.w3.org/TR/REC-xml/#sec-pi">XML specification section: Processing Instructions</a></li> <li><a href="https://web.archive.org/web/20160303185749/http://www.dpawson.co.uk/xsl/sect2/N6145.html">XSLT FAQ: Processing Instructions</a>, Dave Pawson</li> <li><a href="https://developer.mozilla.org/en/XSLT/processing-instruction">xslt:processing-instruction</a>, Mozilla</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Stayton, Bob (September 2007). "Chapter 9. Customization methods §Processing instructions". DocBook XSL: The Complete Guide. Sagehill Enterprises. ISBN 978-0974152134. <a href="978-0974152134" target="_blank">978-0974152134</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Comparison of SGML and XML; World Wide Web Consortium Note, 15 December 1997 <a href="http://www.w3.org/TR/NOTE-sgml-xml-971215" target="_blank">http://www.w3.org/TR/NOTE-sgml-xml-971215</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Bryan, Martin (1997). SGML and HTML Explained. Addison Wesley Longman. ISBN 0-201-40394-3. Retrieved 2010-08-18. <a href="0-201-40394-3" target="_blank">0-201-40394-3</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Hossein Bidgoli (2004). The Internet encyclopedia, Volume 3. John Wiley and Sons. p. 877. ISBN 0-471-22203-8. <a href="0-471-22203-8" target="_blank">0-471-22203-8</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>"XML 1.0 - slide "Processing Instructions (PIs)"". www.w3.org. Retrieved 2023-02-08. <a href="https://www.w3.org/Consortium/Offices/Presentations/XML1.0/slide30-0.htm" target="_blank">https://www.w3.org/Consortium/Offices/Presentations/XML1.0/slide30-0.htm</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Elliotte Rusty Harold, W. Scott Means (2004). XML in a nutshell. p. 23. ISBN 978-0-596-00764-5. <a href="978-0-596-00764-5" target="_blank">978-0-596-00764-5</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>"Associating Style Sheets with XML documents 1.0 (Second Edition)". <a href="http://www.w3.org/TR/xml-stylesheet/" target="_blank">http://www.w3.org/TR/xml-stylesheet/</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Part 2. FO Processing Instruction Reference". <a href="http://docbook.sourceforge.net/release/xsl/current/doc/pi/pi-fo.html" target="_blank">http://docbook.sourceforge.net/release/xsl/current/doc/pi/pi-fo.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>"Robots Processing Instruction Homepage". Archived from the original on 2010-09-21. Retrieved 2010-08-18. <a href="https://web.archive.org/web/20100921021126/http://www.atrus.org/writings/technical/robots_pi/" target="_blank">https://web.archive.org/web/20100921021126/http://www.atrus.org/writings/technical/robots_pi/</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> </ol>