[e] (0) Clarify how to handle unknown language codes.

Fixing http://www.w3.org/Bugs/Public/show_bug.cgi?id=8151 git-svn-id: http://svn.whatwg.org/webapps@4454 340c8d12-0b0e-0410-8428-c7bf67bfef74
whatwg · Dec 19, 2009 · 68d75b6 · 68d75b6
1 parent f5ebec7
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Showing 3 changed files with 41 additions and 6 deletions.
diff --git a/complete.html b/complete.html
@@ -8134,8 +8134,19 @@ <h5 id=the-lang-and-xml:lang-attributes><span class=secno>3.2.3.3 </span>The <co
   unknown (the empty string).</p>
 
   <p>If the resulting value is not a recognized language code, then it
-  must be treated as an unknown language (as if the value was the
-  empty string).</p>
+  must be treated as an unknown language having the given language
+  code, distinct from all other languages. For the purposes of
+  round-tripping or communicating with other services that expect
+  language codes, user agents should pass unknown language codes
+  through unmodified.</p>
+
+  <p class=example>Thus, for instance, an element with <code title="">lang="xyzzy"</code> would be matched by the selector <code title="">:lang('xyzzy')</code> (e.g. in CSS), but it would not be
+  matched by <code title="">:lang('abcde')</code>, even though both
+  are equally invalid. Similarly, if a Web browser and screen reader
+  working in unison communicated about the language of the element,
+  the browser would tell the screen reader that the language was
+  "xyzzy", even if it knew it was invalid, just in case the screen
+  reader actually supported a language with that code after all.</p>
 
   <hr><p>User agents may use the element's language to determine proper
   processing or rendering (e.g. in the selection of appropriate

diff --git a/index b/index
@@ -7969,8 +7969,19 @@ Transport Protocol"&gt;HTTP&lt;/abbr&gt; today.&lt;/p&gt;</pre>
   unknown (the empty string).</p>
 
   <p>If the resulting value is not a recognized language code, then it
-  must be treated as an unknown language (as if the value was the
-  empty string).</p>
+  must be treated as an unknown language having the given language
+  code, distinct from all other languages. For the purposes of
+  round-tripping or communicating with other services that expect
+  language codes, user agents should pass unknown language codes
+  through unmodified.</p>
+
+  <p class=example>Thus, for instance, an element with <code title="">lang="xyzzy"</code> would be matched by the selector <code title="">:lang('xyzzy')</code> (e.g. in CSS), but it would not be
+  matched by <code title="">:lang('abcde')</code>, even though both
+  are equally invalid. Similarly, if a Web browser and screen reader
+  working in unison communicated about the language of the element,
+  the browser would tell the screen reader that the language was
+  "xyzzy", even if it knew it was invalid, just in case the screen
+  reader actually supported a language with that code after all.</p>
 
   <hr><p>User agents may use the element's language to determine proper
   processing or rendering (e.g. in the selection of appropriate

diff --git a/source b/source
@@ -8087,8 +8087,21 @@ Transport Protocol">HTTP&lt;/abbr> today.&lt;/p></pre>
   unknown (the empty string).</p>
 
   <p>If the resulting value is not a recognized language code, then it
-  must be treated as an unknown language (as if the value was the
-  empty string).</p>
+  must be treated as an unknown language having the given language
+  code, distinct from all other languages. For the purposes of
+  round-tripping or communicating with other services that expect
+  language codes, user agents should pass unknown language codes
+  through unmodified.</p>
+
+  <p class="example">Thus, for instance, an element with <code
+  title="">lang="xyzzy"</code> would be matched by the selector <code
+  title="">:lang('xyzzy')</code> (e.g. in CSS), but it would not be
+  matched by <code title="">:lang('abcde')</code>, even though both
+  are equally invalid. Similarly, if a Web browser and screen reader
+  working in unison communicated about the language of the element,
+  the browser would tell the screen reader that the language was
+  "xyzzy", even if it knew it was invalid, just in case the screen
+  reader actually supported a language with that code after all.</p>
 
   <hr>