Status: Level 1 - Proposed
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 meta-information.
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:
http-equiv
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 header.
name
Meta-information name. If not present, the name can be
assumed equal to the value of
http-equiv.
content
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="fielding@ics.uci.edu (Roy Fielding)">
Expires: Tue, 04 Dec 1993 21:29:02 GMT
Keywords: Fred, Barney
Reply-to: fielding@ics.uci.edu (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.