[ac] (0) WF2: Allow placeholder='' to be empty. No need to be overzea…

…lous in our requirements. (credit: sp)

git-svn-id: http://svn.whatwg.org/webapps@2527 340c8d12-0b0e-0410-8428-c7bf67bfef74

index

@@ -26975,9 +26975,8 @@ You cannot complete this form until the field is correct.</samp></pre>
   attribute represents a <em>short</em> hint (a word or short phrase)
   intended to aid the user with data entry. A hint could be a sample
   value or a brief description of the expected format. The attribute,
-  if specified, must have a value that is not the empty string and
-  that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN
-  (CR) characters.</p>
+  if specified, must have a value that contains no U+000A LINE FEED
+  (LF) or U+000D CARRIAGE RETURN (CR) characters.</p>
 
   <p class=note>For a longer hint or other advisory text, the <code title=attr-title><a href=#the-title-attribute>title</a></code> attribute is more appropriate.</p>
 

source

@@ -30188,9 +30188,8 @@ You cannot complete this form until the field is correct.</samp></pre>
   attribute represents a <em>short</em> hint (a word or short phrase)
   intended to aid the user with data entry. A hint could be a sample
   value or a brief description of the expected format. The attribute,
-  if specified, must have a value that is not the empty string and
-  that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN
-  (CR) characters.</p>
+  if specified, must have a value that contains no U+000A LINE FEED
+  (LF) or U+000D CARRIAGE RETURN (CR) characters.</p>
 
   <p class="note">For a longer hint or other advisory text, the <code
   title="attr-title">title</code> attribute is more appropriate.</p>