Re: browsing vs validation, or, why not to make software robust

Tim Berners-Lee (
Fri, 20 Aug 93 17:19:31 +0200

I support Marc completely in his decision to make Mosaic
work as best it can when it is given invalid HTML. The
maxim is that one should be
- conservative in what one does
- liberal in what one expects.

In other words, generate good HTML and expect nothing.

When Terry says the DTD is the basis for chaking HTML,
he means you can get SGMLS, concatenate the DTD in the
spoec with any HTML document, and run it through SGMLS
to get a list of errors.

That is the author's job. We have considered making a
"policeman" program to do it all over the web and mail
or throw rotten eggs at authors, but we are not in
a position to do it yet! Arthur
Secret has been checking our directory space for bad files
and opening them and re-saving them with the NeXT editor
(WorldWideWeb app) to fix them. This will only work where the
editor's liberal interpretation was correct, but it will
certainly cure files written with old versions of the same

Tim BL

Begin forwarded message:

From: Terry Allen <>
Date: Wed, 18 Aug 1993 16:10:55 PDT
In-Reply-To: (Marc Andreessen)
"browsing vs validation, or, why not to make software robust"
(Aug 18, 6:00pm)

No lint is needed; we have a DTD. That's supposed to be our
interface between documents and browsers. If you don't want to
report errors, well, we'll have to live with that. But if you
aren't planning on using the HTML+ DTD as an interface with us
document editors, please tell us now.