[ac] (1) Tweaks to requirements for encoding declarations and support

git-svn-id: http://svn.whatwg.org/webapps@959 340c8d12-0b0e-0410-8428-c7bf67bfef74

index

@@ -7677,15 +7677,15 @@ class="main"> or <div class="content">. Why do we also need a body?
    <li>The character encoding name given must be the name of the character
     encoding used to serialise the file.
 
-   <li>The value must be a valid character encoding name. <a
+   <li>The value must be a valid character encoding name, and must be the
+    preferred name for that encoding. <a
     href="#refsIANACHARSET">[IANACHARSET]</a> <!-- XXX
    http://www.iana.org/assignments/character-sets -->
 
    <li>The attribute value must be serialised without the use of character
     entity references of any kind.
-
-   <li>
   </ul>
+  <!-- XXX next three paragraphs maybe should move to "writing html" section -->
 
   <p>If the document does not start with a BOM, and if its encoding is not
    explicitly given by <a href="#content-type8"
@@ -7708,6 +7708,9 @@ class="main"> or <div class="content">. Why do we also need a body?
    href="#refsSCSU">[SCSU]</a></p>
   <!-- XXX ref JIS_X0212-1990, x-JIS0208, EBCDIC, UTF-32 -->
 
+  <p>Authors are encouraged to use UTF-8. Conformance checkers may advise
+   against authors using legacy encodings.
+
   <p>In XHTML, the XML declaration should be used for inline character
    encoding information, if necessary.
 
@@ -33463,6 +33466,17 @@ function receiver(e) {
      may heuristically decide which to use as a default.
   </ol>
 
+  <p>User agents must at a minimum support the UTF-8 and Windows-1252
+   encodings, but may support more.
+
+  <p class=note>It is not unusual for Web browsers to support dozens if not
+   upwards of a hundred distinct character encodings.
+
+  <p>User agents must support the preferred MIME name of every character
+   encoding they support that has a preferred MIME name, and should support
+   all the IANA-registered aliases. <a
+   href="#refsIANACHARSET">[IANACHARSET]</a>
+
   <h5 id=preprocessing><span class=secno>8.2.2.2. </span>Preprocessing the
    input stream</h5>
 

source

@@ -6265,17 +6265,18 @@ class="main"> or <div class="content">. Why do we also need a body?
    <li>The character encoding name given must be the name of the
    character encoding used to serialise the file.</li>
 
-   <li>The value must be a valid character encoding name. <a
+   <li>The value must be a valid character encoding name, and must be
+   the preferred name for that encoding. <a
    href="#refsIANACHARSET">[IANACHARSET]</a> <!-- XXX
    http://www.iana.org/assignments/character-sets --></li>
 
    <li>The attribute value must be serialised without the use of
    character entity references of any kind.</li>
 
-   <li>
-
   </ul>
 
+  <!-- XXX next three paragraphs maybe should move to "writing html" section -->
+
   <p>If the document does not start with a BOM, and if its encoding is
   not explicitly given by <span title="Content-Type">Content-Type
   metadata</span>, then the character encoding used must be a superset
@@ -6294,6 +6295,9 @@ class="main"> or <div class="content">. Why do we also need a body?
   href="#refsBOCU1">[BOCU1]</a> <a href="#refsSCSU">[SCSU]</a></p>
   <!-- XXX ref JIS_X0212-1990, x-JIS0208, EBCDIC, UTF-32 -->
 
+  <p>Authors are encouraged to use UTF-8. Conformance checkers may
+  advise against authors using legacy encodings.</p>
+
   <p>In XHTML, the XML declaration should be used for inline character
   encoding information, if necessary.</p>
 
@@ -30972,6 +30976,17 @@ function receiver(e) {
 
   </ol>
 
+  <p>User agents must at a minimum support the UTF-8 and Windows-1252
+  encodings, but may support more.</p>
+
+  <p class="note">It is not unusual for Web browsers to support dozens
+  if not upwards of a hundred distinct character encodings.</p>
+
+  <p>User agents must support the preferred MIME name of every
+  character encoding they support that has a preferred MIME name, and
+  should support all the IANA-registered aliases. <a
+  href="#refsIANACHARSET">[IANACHARSET]</a></p>
+
 
   <h5>Preprocessing the input stream</h5>