On February 25, 1993, Marc Andreessen wrote:
I'd like to propose a new, optional HTML tag:
Required argument is
This names a bitmap or pixmap file for the browser to attempt to pull over the network and interpret as an image, to be embedded in the text at the point of the tag's occurrence.
An example is:
(There is no closing tag; this is just a standalone tag.)
This tag can be embedded in an anchor like anything else; when that happens, it becomes an icon that's sensitive to activation just like a regular text anchor.
Browsers should be afforded flexibility as to which image formats they support. Xbm and Xpm are good ones to support, for example. If a browser cannot interpret a given format, it can do whatever it wants instead (X Mosaic will pop up a default bitmap as a placeholder).
This is required functionality for X Mosaic; we have this working, and we'll at least be using it internally. I'm certainly open to suggestions as to how this should be handled within HTML; if you have a better idea than what I'm presenting now, please let me know. I know this is hazy wrt image format, but I don't see an alternative than to just say ``let the browser do what it can'' and wait for the perfect solution to come along (MIME, someday, maybe).
“Mosaic” was one of the earliest web browsers. ("X Mosaic" was the version that ran on Unix systems.) When he wrote this message in early 1993, Marc Andreessen had not yet founded the company that made him famous, Mosaic Communications Corporation, nor had he started work on that company's flagship product, “Mosaic Netscape.” (You may know them better by their later names, "Netscape Corporation" and “Netscape Navigator.”)
“MIME, someday, maybe” is a reference to content negotiation, a feature of HTTP where a client (like a web browser) tells the server (like a web server) what types of resources it supports (like
image/jpeg) so the server can return something in the client's preferred format. The Original HTTP as defined in 1991 (the only version that was implemented in February 1993) did not have a way for clients to tell servers what kind of images they supported, thus the design dilemma that Marc faced.
A few hours later, Tony Johnson replied:
I have something very similar in Midas 2.0 (in use here at SLAC, and due for public release any week now), except that all the names are different, and it has an extra argument
NAME="name". It has almost exactly the same functionality as your proposed
<ICON name="NoEntry" href="http://note/foo/bar/NoEntry.xbm">
The idea of the name parameter was to allow the browser to have a set of "built in" images. If the name matches a "built in" image it would use that instead of having to go out and fetch the image. The name could also act as a hint for "line mode" browsers as to what kind of a symbol to put in place of the image.
I don't much care about the parameter or tag names, but it would be sensible if we used the same things. I don't much care for abbreviations, ie why not
SOURCE=. I somewhat prefer
ICONsince it imlies that the
IMAGEshould be smallish, but maybe
ICONis an overloaded word?
Midas was another early web browser, a contemporary of X Mosaic. It was cross-platform; it ran on both Unix and VMS. “SLAC” refers to the Stanford Linear Accelerator Center (now the SLAC National Accelerator Laboratory). SLAC hosted the first web server in the United States (in fact the first web server outside Europe). When Tony wrote this message, SLAC was an old-timer on the WWW, having hosted five pages on their web server for a whopping 441 days.
While we are on the subject of new tags, I have another, somewhat similar tag, which I would like to support in Midas 2.0. In principle it is:
The intention here would be that the second document is to be included into the first document at the place where the tag occured. In principle the referenced document could be anything, but the main purpose was to allow images (in this case arbitrary sized) to be embedded into documents. Again the intention would be that when HTTP2 comes along the format of the included document would be up for separate negotiation.
“HTTP2” is a reference to Basic HTTP as defined in 1992. At this point in early 1993, it was still largely unimplemented. The draft known as “HTTP2” evolved and was eventually standardized as “HTTP 1.0” (albeit not for another three years). HTTP 1.0 did include request headers for content negotiation, a.k.a. “MIME, someday, maybe.”
An alternative I was considering was:
<A HREF="..." INCLUDE>See photo</A>
I don't much like adding more functionality to the
<A>tag, but the idea here is to maintain compatibility with browsers that can not honour the
INCLUDEparameter. The intention is that browsers which do understand
INCLUDE, replace the anchor text (in this case "See photo") with the included document (picture), while older or dumber browsers ignore the
This proposal was never implemented, although the idea of text-if-an-image-is-missing is an important accessibility technique which was missing from Marc’s initial
<IMG> proposal. Many years later, this feature was bolted on as the
<img alt> attribute, which Netscape promptly broke by erroneously treating it as a tooltip.
A few hours after that, Tim Berners-Lee responded:
I had imagined that figues would be reprented as
<a name=fig1 href="fghjkdfghj" REL="EMBED, PRESENT">Figure </a>
where the relation ship values meanEMBED Embed this here when presenting it PRESENT Present this whenever the source document is presented
Note that you can have various combinations of these, and if the browser doesn't support either one, it doesn't break.
[I] see that using this as a method for selectable icons means nesting anchors. Hmmm. But I hadn't wanted a special tag.
This proposal was never implemented, but the
rel attribute is still around.
It would be nice if there was a way to specify the content type, e.g.
<IMG HREF="http://nsa.gov/pub/sounds/gorby.au" CONTENT-TYPE=audio/basic>
But I am completely willing to live with the requirement that I specify the content type by file extension.
This proposal was never implemented, but Netscape did later add arbitrary embedding of media objects with the
While images are at the top of my list of desired medium types in a WWW browser, I don't think we should add idiosyncratic hooks for media one at a time. Whatever happened to the enthusiasm for using the MIME typing mechanism?
This isn't a substitute for the upcoming use of MIME as a standard document mechanism; this provides a necessary and simple implementation of functionality that's needed independently from MIME.
Let's temporarily forget about MIME, if it clouds the issue. My objection was to the discussion of "how are we going to support embedded images" rather than "how are we going to support embedded objections in various media".
Otherwise, next week someone is going to suggest 'lets put in a new tag
<AUD SRC="file://foobar.com/foo/bar/blargh.snd">' for audio.
There shouldn't be much cost in going with something that generalizes.
Responding to Jay’s original message, Dave Raggett said:
True indeed! I want to consider a whole range of possible image/line art types, along with the possibility of format negotiation. Tim's note on supporting clickable areas within images is also important.
Later in 1993, Dave Raggett proposed HTML+ as an evolution of the HTML standard. The proposal was never implemented, and it was superceded by HTML 2.0. HTML 2.0 was a “retro-spec,” which means it formalized features already in common use. “This specification brings together, clarifies, and formalizes a set of features that roughly corresponds to the capabilities of HTML in common use prior to June 1994.”
Dave later wrote HTML 3.0, based on his earlier HTML+ draft. HTML 3.0 was also never implemented (outside of the W3C’s own reference implementation, Arena), and it was superceded by HTML 3.2. HTML 3.2 was also a “retro-spec” — “HTML 3.2 adds widely deployed features such as tables, applets and text flow around images, while providing full backwards compatibility with the existing standard HTML 2.0.”
Getting back to 1993, Marc replied to Dave:
Actually, maybe we should think about a general-purpose procedural graphics language within which we can embed arbitrary hyperlinks attached to icons, images, or text, or anything. Has anyone else seen Intermedia's capabilities wrt this?
The idea of a “general-purpose procedural graphics language” did eventually catch on. Modern browsers support both SVG (declarative markup with embedded scripting) and
<canvas> (procedural direct-mode graphics API), although the latter started as a proprietary extension before being “retro-specced” by the WHATWG.
Other systems to look at which have this (fairly valuable) notion are Andrew and Slate. Andrew is built with _insets_, each of which has some interesting type, such as text, bitmap, drawing, animation, message, spreadsheet, etc. The notion of arbitrary recursive embedding is present, so that an inset of any kind can be embedded in any other kind which supports embedding. For example, an inset can be embedded at any point in the text of the text widget, or in any rectangular area in the drawing widget, or in any cell of the spreadsheet.
Meanwhile, Thomas Fine had a different idea:
Here's my opinion. The best way to do images in WWW is by using MIME. I'm sure postscript is already a supported subtype in MIME, and it deals very nicely with mixing text and graphics.
But it isn't clickable, you say? Yes your right. I suspect there is already an answer to this in display postscript. Even if there isn't the addition to standard postscript is trivial. Define an anchor command which specifies the URL and uses the current path as a closed region for the button. Since postscript deals so well with paths, this makes arbitrary button shapes trivial.
Display Postscript was an on-screen rendering technology co-developed by Adobe and NeXT.
This proposal was never implemented, but the idea that the best way to fix HTML is to replace it with something else altogether still pops up from time to time.
HTTP2 allows a document to contain any type which the user has said he can handle, not just registered MIME types. So one can experiment. Yes I think there is a case for postscript with hypertext. I don't know whether display postcript has enough. I know Adobe are trying to establish their own postscript-based "PDF" which will have links, and be readable by their proprietory brand of viewers.
I thought that a generic overlaying language for anchors (Hytime based?) would allow the hypertext and the graphics/video standards to evolve separately, which would help both.
INCLUDEand let it refer to an arbitrary document type. Or
INCLUDEsounds like a cpp include which people will expect to provide SGML source code to be parsed inline -- not what was intended.
HyTime was an early, SGML-based hypertext document system. It loomed large in many early discussions of HTML, and later XML.
Tim’s proposal for an
<INCLUDE> tag was never implemented, although you can see echoes of it in
<embed>, and the
Finally, on March 12, 1993, Marc Andreessen revisited the thread:
Back to the inlined image thread again -- I'm getting close to releasing Mosaic v0.10, which will support inlined GIF and XBM images/bitmaps, as mentioned previously. ...
We're not prepared to support
EMBEDat this point. ... So we're probably going to go with
ICON, since not all inlined images can be meaningfully called icons). For the time being, inlined images won't be explicitly content-type'd; down the road, we plan to support that (along with the general adaptation of MIME). Actually, the image reading routines we're currently using figure out the image format on the fly, so the filename extension won't even be significant.
I don’t really know why I wrote this. It wasn’t what I set out to write. That happens. But I am extraordinarily fascinated with all aspects of this almost-17-year-old conversation. Consider:
But none of this answers the original question: why do we have an
<img> element? Why not an
<icon> element? Or an
<include> element? Why not a hyperlink with an
include attribute, or some combination of
rel values? Why an
<img> element? Quite simply, because Marc Andreessen shipped one, and shipping code wins.
That’s not to say that all shipping code wins; after all, Andrew and Intermedia and HyTime shipped code too. Code is necessary but not sufficient for success. And I certainly don’t mean to say that shipping code before a standard will produce the best solution. Marc’s
<img> element didn’t mandate a common graphics format; it didn’t define how text flowed around it; it didn’t support text alternatives or fallback content for older browsers. And 16, almost 17 years later, we’re still struggling with content sniffing, and it’s still a source of crazy security vulnerabilities. And you can trace that all the way back, 17 years, through the Great Browser Wars, all the way back to February 25, 1993, when Marc Andreessen offhandedly remarked, “MIME, someday, maybe,” and then shipped his code anyway.
The ones that win are the ones that ship.