Re: Meta info tags (was Re: what finger tags?)

Roy T. Fielding (fielding@avron.ICS.UCI.EDU)
Sun, 18 Sep 1994 22:05:46 -0700

> META looks like this:
> <META name="TITLE" value="Rotkaeppchen">
> <META name="YEAR" value="1990">

I'll send a longer follow-up to www-html, but this needs to be said here.
The syntax for the META element was changed in June for the HTML 2.0 spec.
It is now defined as follows:


The meta element is proposed to be used within the head element to
embed document meta-information not defined by other HTML
elements. Such information can be extracted by servers/clients for use
in identifying, indexing, and cataloging specialized document

Although it is generally preferable to use named elements which have
well-defined semantics for each type of meta-information (e.g. title),
this element is provided for situations where strict SGML parsing is
necessary and the local DTD is not extensible.

In addition, HTTP servers can read the content of the document head to
generate response headers corresponding to any elements defining a
value for the attribute HTTP-EQUIV. This provides document authors a
mechanism (not necessarily the preferred one) for identifying
information which should be included in the response headers for an
HTTP request.

The attributes of the meta element are:


This attribute binds the element to an HTTP response header. It
means that if you know the semantics of the HTTP response header
named by this attribute, then you can process the contents based on a
well-defined syntactic mapping, whether or not your DTD tells you
anything about it. HTTP header names are not case sensitive. If not
present, the attribute name should be used to identify this
meta-information and it should not be used within an HTTP response


Meta-information name. If not present, the name can be assumed
equal to the value of http-equiv.


The meta-information content to be associated with the given name
and/or HTTP response header.


If the document contains:

<expires http-equiv="Expires">Tue, 04 Dec 1993 21:29:02 GMT</expires>
<meta http-equiv="Keywords" content="Fred, Barney">
<meta http-equiv="Reply-to" content=" (Roy Fielding)">

the resulting HTTP response headers would be

Expires: Tue, 04 Dec 1993 21:29:02 GMT
Keywords: Fred, Barney
Reply-to: (Roy Fielding)

when the http-equiv attribute is not present, the server should not
generate an HTTP response header for this meta-information; e.g.,

<meta name="IndexType" content="Service">

Do not use the meta element to define information that should be
associated with an already existing HTML element. This is an
inappropriate use of the meta element:

<meta name="Title" content="The Etymology of Dunsel">

Do not name an http-equiv equal to a response header that should
normally only be generated by the HTTP server. Example names that are
inappropriate include "Server", "Date", and "Last-modified" -- the
exact list of inappropriate names is dependent on the particular
server implementation. It is recommended that servers ignore any meta
elements which specify http-equivalents which are equal
(case-insensitively) to their own reserved response headers.

......Roy Fielding ICS Grad Student, University of California, Irvine USA