[dbaron revision history] Add vendor text from Bert. Fix some references. (date: 2003/07/14 18:46:13)

Author: dbaron

css3-syntax/Overview.src.html

@@ -151,7 +151,7 @@ <h2>CSS style sheet representation</h2>
 <li>A character set specified by a higher level protocol (e.g., the
 "charset" parameter to the MIME type specified in an HTTP "Content-Type"
 field).
-(The HTTP protocol ([[RFC2616]], section 3.7.1) mentions ISO-8859-1 as a
+(The HTTP protocol ([[HTTP11]], section 3.7.1) mentions ISO-8859-1 as a
 default character encoding when the "charset" parameter is absent from
 the "Content-Type" header field. In practice, this recommendation has
 proved useless because some servers don't allow a "charset" parameter to
@@ -262,9 +262,9 @@ <h3 id="text-css"><span class="index-def" title="text/css">The text/css content
 information<!--(see [[HTML40]], chapter 5)-->. The structure of the
 transmission, termed a <span class="index-def" title="message
 entity"><a name="message-entity"><strong>message
-entity,</strong></a></span> is defined by RFC 2045 and RFC 2068 (see
-[[RFC2045]] and [[RFC2068]]). A message entity with a content type of
-"text/css" represents an independent CSS document. The "text/css"
+entity,</strong></a></span> is defined by MIME and HTTP 1.1 (see
+[[!RFC2045]] and [[!HTTP11]]). A message entity with a content type of
+"text/css" represents an independent CSS style sheet. The "text/css"
 content type has been registered by RFC 2318 ([[!RFC2318]]).</p>
 
 <h2 id="syntax">General syntax of CSS</h2>
@@ -936,33 +936,63 @@ <h3>Partial implementations</h3>
 
 <h2>Vendor-specific extensions</h2>
 
-<p>
-  CSS3, unlike CSS1 or CSS2, allows identifiers to begin with <span
-  class="css">'-'</span>.  <span class="issue">[Should the grammar allow
-  '-' as part of identifiers or should it require that vendors who use '-' to
-  begin identifiers extend the grammar in their tokenizer?]</span> Property
-  names and keywords beginning with <span class="css">'-'</span> are reserved
-  for vendor-specific extensions.  Property names and keywords in
-  vendor-specific extensions should have the format
-</p>
+<p>Although proprietary extensions should be avoided in general, there
+are situations (experiments, implementations of W3C drafts that have not
+yet reached Candidate Recommendation, intra-nets, debugging, etc.) where
+it is convenient to add some nonstandard, i.e., proprietary identifiers
+to a CSS style sheet. It is often hard to predict how long these
+proprietary extensions will be in use and hard to avoid that their names
+clash with new, standard properties or with other proprietary
+properties. Therefore the CSS Working Group proposes the following
+simple naming convention. A proprietary name should have a prefix
+consisting of:</p>
 
-<pre>
-'-' + vendor identifier + '-' + meaningful name
-</pre>
+<ol>
+  <li>an underscore ("_") or a dash ("-"),</li>
+  <li>the (possibly abbreviated) name of the company, organization, etc. that
+    created it,</li>
+  <li>an underscore or a dash.</li>
+</ol>
 
-<p>
+<p>Some examples (and the companies/organizations that created them):</p>
+<ul>
+  <li><em>-moz-box-sizing,</em> <em>-moz-border-radius</em> (The Mozilla
+    Organization)</li>
+  <li><em>-wap-accesske</em>y (The WAP Forum)</li>
+  <li><em>_xyz-dwiw</em> (hypothetical)</li>
+</ul>
 
-  For example, if XYZ Corp. added a property to describe the color
-  of the border on the East side of the display, they might
-  call it <span class="css">-xyz-border-east-color</span>.  Other
-  CSS implementations will not recognize the property and will
-  ignore it according to the <a href="#parsing-errors">rules
-  for handling parsing errors</a>.
+<p>The advantage of the initial dash is that it is not a valid start character
+for identifiers in CSS, so it is guaranteed never to be used by any current or
+future level of CSS. CSS-conforming parsers will skip rules that contain
+identifiers with such a character.
+<span class="issue">[Should the grammar allow
+'-' as part of identifiers or should it require that vendors who use '-' to
+begin identifiers extend the grammar in their tokenizer?  Currently it
+does, but perhaps it shouldn't.]</span></p>
 
-</p>
+<p>That is also a possible disadvantage: a conforming parser will skip them,
+so in order to use them, an extended parser is required.</p>
+
+<p>For that reason, the underscore is also proposed. Although it is a valid
+start character, the CSS Working Group believes it will never define any
+identifiers that start with that character.</p>
+
+<h3 class="no-num no-toc">Historical notes</h3>
 
-<p class="issue">This needs to be reconciled with <a
-href="../css3-naming/">Bert's document</a> describing the same thing.</p>
+<p>Microsoft created a number of proprietary properties for use inside their
+Microsoft Office product, at a time when there was not yet a consensus in the
+working group about the naming convention. They chose to prefix properties
+with "mso-" rather than "-mso-".</p>
+
+<p>At the time of writing, the following prefixes are known to exist:</p>
+<ul>
+  <li><em>mso-</em> (Microsoft Corporation)</li>
+  <li><em>-moz-</em> (The Mozilla Organization)</li>
+  <li><em>-opera-</em> (Opera Software)</li>
+  <li><em>-atsc</em>- (Advanced Television Standards Committee)</li>
+  <li><em>-wap-</em> (The WAP Forum)</li>
+</ul>
 
 <h2>Associating style sheets with documents</h2>
 
@@ -1232,7 +1262,7 @@ <h2 id="conf">Conformance</h2>
 class="index-def" title="RECOMMENDED">"RECOMMENDED"</span>, <span
 class="index-def" title="MAY">"MAY"</span>, and <span
 class="index-def" title="OPTIONAL">"OPTIONAL"</span> in this document
-are to be interpreted as described in RFC&nbsp;2119 (see [[RFC2119]]).
+are to be interpreted as described in RFC&nbsp;2119 (see [[!RFC2119]]).
 However, for readability, these words do not appear in all uppercase
 letters in this specification.</p>
 
@@ -1299,7 +1329,7 @@ <h3>Definitions</h3>
 <dt><strong><span class="index-def" title="element"><a
 name="element">Element</a></span></strong>
 
-<dd>(An SGML term, see [[ISO8879]].) The primary syntactic constructs
+<dd>(An SGML term, see [[!ISO8879]].) The primary syntactic constructs
 of the document language. Most CSS style sheet rules use the names of
 these elements (such as P, TABLE, and OL in HTML) to specify
 how the elements should be rendered.
@@ -1428,7 +1458,7 @@ <h3>Definitions</h3>
 to another format, etc.</dd>
 
 <DD>An HTML user agent is one that supports the HTML 2.x, HTML 3.x, or
-HTML 4.x specifications. A user agent that supports XHTML [[-XHTML]],
+HTML 4.x specifications. A user agent that supports XHTML [[XHTML10]],
 but not HTML (as listed in the previous sentence) is not considered an
 HTML user agent for the purpose of conformance with this
 specification.
@@ -1488,7 +1518,7 @@ <h3 id="conf-UA">User agent conformance</h3>
 href="cascade.html">cascading and inheritance</a>.
 
 <li>If the source document comes with alternate style sheet sets (such as
-with the "alternate" keyword in HTML 4.0 [[-HTML40]]), the UA must
+with the "alternate" keyword in HTML 4.0 [[HTML40]]), the UA must
 allow the user to select which style sheet set the UA should apply.
 
 </ol>