Re: Toward Graceful Deployment of Tables

lilley (
Tue, 14 Mar 1995 16:02:38 +0000 (GMT)

Dan Connolly wrote:

> This is a copy of:

> Documents with tables should be labelled as:
> Content-Type: text/html; level=3
> and clients that support HTML 3.0 will interpret them reliably.

and, later on,

> should information providers use text/x-html; level=3 rather than
> text/html; level=3?

However the current DTD (Draft: Mon 13-Mar-95 09:51:25) states:

While HTML 3.0 is being discussed, please use text/x-html3
as a temporary MIME content type, as this will allow clients
to distinguish html 3 from current html documents.

Which of these three is correct?

Using Netscape 1.1b1 for HP-UX, sending the same table-containing file with
different MIME types, I find:

text/html displays fine
text/html; level=3 displays fine, level is ignored
text/x-html3 unknown media type, offers to save to file
text/x-html; level=3 unknown media type, warning about unknown encoding "level"

This was using the CERN server, version 3.0pre6, like this:

#Add experimental MIME types for CGM files and HTML 3.0
AddType .cgm application/x-cgm 8bit
AddType .html3 text/html; level=3 8bit
AddType .html-3 text/x-html3 8bit
AddType .html+3 text/x-html; level=3 8bit

I think that the server does not allow spaces in the MIME type, even if
there is a semicolon after the subtype. So it is sending out an illegal
encoding. Yup:

cguhpc [79]: telnet info 8080
Connected to
Escape character is '^]'.
HEAD /eg-uk-tables.html+3 HTTP/1.0

HTTP/1.0 200 Document follows
MIME-Version: 1.0
Server: CERN/3.0pre6
Date: Tuesday, 14-Mar-95 15:28:18 GMT
Content-Encoding: level=3
Content-Type: text/x-html;
Content-Length: 1047
Last-Modified: Tuesday, 14-Mar-95 15:10:05 GMT

Connection closed by foreign host.

I have previously reported a problem with Arena 0.94y (I think) not
accepting text/x-html3. It displayed it OK, but running in verbose mode it
was complaining about an unknown media type. This seems to have been fixed:

Arena 0.96p in debug mode shows that it sends an accept header:

Accept: text/x-html3; q=0.800
Accept: text/html; level=3; q=0.900
Accept: text/html; q=0.600

This seems to suggest that the W3O people see text/x-html3 as the interim
type and text/html; level=3 as the type to be used once HTML 3.0 is official
and stable and stuff (with a higher q factor to express a preference, if the
server has a choice).

If Arena 0.96p gets back

Content-Type: text/x-html;

it does this:

HTMIME: MIME content type is text/x-html;, converting to www/present
StreamStack. Constructing stream stack for text/x-html; to www/present
StreamStack. Don't know how to handle this, so put out */* to www/present
HTExtConvert.... input format is text/x-html;.. output format is www/present

and displays it as a text file.

If it gets this:

Content-Type: text/x-html3

Arena 0.96p displays it without fault:

HTMIME: MIME content type is text/x-html3, converting to www/present
StreamStack. Constructing stream stack for text/x-html3 to www/present
HTExtConvert.... input format is text/x-html3.. output format is www/present
Read Socket. 1047 bytes read


a) Arena 0.96p works correctly, iff the MIME type is text/x-html3
b) Netscape 1.1b1 works correctly, in that it does not claim to be an
HTML 3 browser and offers to save unknown MIME typed objects to disk.
This does mean that some documents it could infact handle are not displayed.
c) The CERN server has problems serving up parameterised MIME types.

Chris Lilley
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