- From: Eliot Graff via cvs-syncmail <cvsmail@w3.org>
- Date: Thu, 17 Mar 2011 20:09:57 +0000
- To: public-html-commits@w3.org
Update of /sources/public/html5/html-xhtml-author-guide In directory hutz:/tmp/cvs-serv18202 Modified Files: html-xhtml-authoring-guide.html Log Message: Edited section 3 per bug 12062, comments 13-14; Index: html-xhtml-authoring-guide.html =================================================================== RCS file: /sources/public/html5/html-xhtml-author-guide/html-xhtml-authoring-guide.html,v retrieving revision 1.68 retrieving revision 1.69 diff -u -d -r1.68 -r1.69 --- html-xhtml-authoring-guide.html 14 Mar 2011 21:03:45 -0000 1.68 +++ html-xhtml-authoring-guide.html 17 Mar 2011 20:09:55 -0000 1.69 @@ -14,7 +14,7 @@ <a href="http://www.w3.org/"><img height="48" width="72" alt="W3C" src="http://www.w3.org/Icons/w3c_home"/></a> </p> <h1 class="title" id="title">Polyglot Markup: HTML-Compatible XHTML Documents</h1> - <h2 id="w3c-editor-s-draft-05-january-2011">W3C Editor's Draft 4 March 2011</h2> + <h2 id="w3c-editor-s-draft-17-march-2011">W3C Editor's Draft 17 March 2011</h2> <dl> <dt>This version:</dt> <dd><a href="http://dev.w3.org/html5/html-xhtml-author-guide/html-xhtml-authoring-guide.html">http://dev.w3.org/html5/html-xhtml-author-guide/html-xhtml-authoring-guide.html</a></dd> @@ -243,38 +243,32 @@ <div id="character-encoding" class="section"> <!--OddPage--><h2><span class="secno">3. </span>Specifying a Document's Character Encoding</h2> <p> - <a class="internalDFN" href="#dfn-polyglot-markup" title="polyglot markup">Polyglot markup</a> declares character encoding in the following ways, which may be used separately or in combination - (if used in combination, each approach contains identical encoding information): + Polyglot markup uses the UTF-8 character encoding, the only character encoding for which both HTML and XML require support. + HTML requires UTF-8 to be explicitly declared to avoid <a href="http://www.w3.org/TR/html5/semantics.html#charset">fallback to a legacy encoding</a> [<cite><a href="#bib-HTML5" rel="biblioentry" class="bibref">HTML5</a></cite>]. + For XML, UTF-8 is an <a href="http://www.w3.org/TR/2008/REC-xml-20081126/#charencoding">encoding default</a>. + As such, character encoding <em title="may" class="rfc2119">may</em> be left undeclared in XML with the result that UTF-8 is still supported [<cite><a href="#bib-XML10" rel="biblioentry" class="bibref">XML10</a></cite>]. + </p> + <p> + <a class="internalDFN" href="#dfn-polyglot-markup" title="polyglot markup">Polyglot markup</a> declares the UTF-8 character encoding in the following ways, which may be used separately or in combination: </p><ul> <li>Within the document</li> <ul> <li>By using the Byte Order Mark (BOM) character (preferred).</li> - <li>By relying on UTF-8 as the encoding default of XML, used in combination with the HTML <code><meta charset="UTF-8"/></code> element.</li> + <li>By using <code><meta charset="UTF-8"/></code> (the HTML encoding declaration).</li> </ul> - <li>In the HTTP header of the response [<cite><a href="#bib-HTTP11" rel="biblioentry" class="bibref">HTTP11</a></cite>], as in the following: - <p> - <code>Content-type: text/html; charset=utf-8</code> - </p> - Note that <a class="internalDFN" href="#dfn-polyglot-markup">polyglot markup</a> may use either <code>text/html</code> or <code>application/xhtml+xml</code> for the value of the content type. + <li>Outside the document + <ul> + <li>By adding <code>"charset=utf-8"</code> to the MIME/HTTP Content-Type header [<cite><a href="#bib-HTTP11" rel="biblioentry" class="bibref">HTTP11</a></cite>], as the following examples show in HTML and XML, respectively: </li> + </ul> + <pre class="example"><code>Content-type: text/html; charset=utf-8</code></pre> + <pre class="example"><code>Content-type: application/xhtml+xml; charset=utf-8</code></pre> </li> </ul> <p></p> - <p> - Using <code><meta charset="*"/></code> has no effect in XML. - Therefore, <a class="internalDFN" href="#dfn-polyglot-markup">polyglot markup</a> may use <code><meta charset="*"/></code> provided the document is encoded as UTF-8 and the value of charset is a case-insensitive match for the string "utf-8". - </p> - <p> - <a class="internalDFN" href="#dfn-polyglot-markup" title="polyglot markup">Polyglot markup</a> uses UTF-8 encoding. - The BOM character <em title="may" class="rfc2119">may</em> be used with the UTF-8 encoding (see <a href="http://dev.w3.org/html5/spec/syntax.html#writing">Writing HTML documents</a> in [<cite><a href="#bib-HTML5" rel="biblioentry" class="bibref">HTML5</a></cite>]), - - and using the BOM character is preferred to not using the BOM -character. - Because the construct of the BOM character is the same for XML and -HTML (unlike the encoding declaration inside the HTTP Content-Type -header), - and because the BOM character works in both XML and HTML (unlike the <code><meta charset="UTF-8"/></code> declaration of HTML and - the UTF-8 encoding default of XML), - the BOM character can be said to be the most polyglot encoding declaration. + <p class="note"> + The HTML encoding declaration has no effect in XML. + When the HTML encoding declaration is the only encoding declaration, +the encoding default from XML makes XML parsers treat content as UTF-8. </p> <p> The <a href="http://www.w3.org/International/questions/qa-html-encoding-declarations">W3C Internationalization (i18n) Group recommends</a> @@ -1052,6 +1046,8 @@ </div> + + <!-- Appendix --> <div id="acknowledgements" class="appendix section"> <h2><span class="secno">A. </span>Acknowledgements</h2>
Received on Thursday, 17 March 2011 20:09:59 UTC