W3C home > Mailing lists > Public > www-talk@w3.org > January to February 1996

Conditional HTML w/<INSERT> (was: Microsoft IE)

From: M. Hedlund <hedlund@best.com>
Date: Mon, 29 Jan 1996 10:12:17 -0800 (PST)
To: John Franks <john@math.nwu.edu>
Cc: www-talk@w3.org
Message-Id: <Pine.SGI.3.91.960129094202.17945B-100000@shellx.best.com>

On Mon, 29 Jan 1996, John Franks wrote:
> One suggestion has been a conditional HTML which is parsed and interpreted
> by the client.  This seems to be a very good idea.  It completely solves
> the caching problem.  One drawback is that documents might become
> substantially larger if they contain all virtual versions.

My recent thinking on this issue is that a form of conditional HTML could
be implemented with <INSERT>.  Give some <PARAM>'s that describe the
conditions under which the insert SRC should be requested, and let the
browser decide whether it should get the insert or not. 

<INSERT SRC="http://www.name.dom/path/table.html" 
   TYPE="text/conditional-html">
<PARAM NAME="condition" VALUE="vendor-tables/1.1">
<P>Your browser doesn't recognize vendor-tables/1.1, so you're seeing 
this instead.</P>
</INSERT>

OR logic could be specified by giving more than one PARAM.  AND logic 
could be specified by recursive INSERTS.  Browsers that don't recognize 
<INSERT> get the fallback text.

Advantages:

* Works in keeping with "the SGML heritage of HTML."

* Doesn't stuff all possible variants into one document (avoids filesize 
  bloat).

* Backwards-compatible.

* Very cache-friendly (not only can primary docs be cached, so can 
  <INSERT>s).

* Avoids stuffing browser capability description into huge Accept header.

Disadvantages:

* Requires multiple GETs (possibly a good number of them).

* Requires the browser to parse the <INSERT>s before issuing subsequent 
  GETs.  (Maybe we can get around this with <ALIAS>?)

The only thing I can say about the first disadvantage is that HTTP is 
moving in a direction that will ease the hit of multiple GETs 
(Keep-Alive, HTTP-ng).

Thoughts?

Marc Hedlund <hedlund@best.com>, <marc@organic.com>
Received on Monday, 29 January 1996 13:16:10 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 27 October 2010 18:14:19 GMT