Re: new html extension proposal

Daniel DuBois (
Mon, 21 Aug 95 12:24:16 -0500

> In this case, ABC-enabled browsers would read the entire IMG tag and
> use /images/ instead of /images/daytona.gif. Old-style
> browsers, who know nothing of X-ALTSRC, would use /images/daytona.gif.
> This format is called "dual encoding.

The functionality described in this X-ALTSRC tag would be very similiar to
the Content Negotiation currently in HTTP. I would be against this HTML
addition if only for the sole reason it would slow down awareness and use of
the existing content negotiation capabilities of HTTP.

For instance, why not have "<IMG SRC=/image/daytona>" in your HTML document,
and then a content negotiating server (like Spyglass Server) will decide
what to send based on your Accept: headers. Smart browsers will send
requests with Accept: headers based on the types they handle, likely giving
higher weight to types they handle intenally and/or inline.

HTTP Content Negotiation already has defined the ability to negotiate
languages, encodings, and characters sets in addition to MIME types.
Dan DuBois, Software Animal
(708) 505-1010 x532