RE: Action item on the virtues of error-handling

On Wed, 2003-10-22 at 11:12, David Orchard wrote:
> html 2.0 rfc 1866 contains the following text in 4.2.1 Undeclared Markup
> Handling
>  To facilitate experimentation and interoperability between
>    implementations of various versions of HTML, the installed base of
>    HTML user agents supports a superset of the HTML 2.0 language by
>    reducing it to HTML 2.0: markup in the form of a start-tag or end-
>    tag, whose generic identifier is not declared is mapped to nothing
>    during tokenization. Undeclared attributes are treated similarly. The
>    entire attribute specification of an unknown attribute (i.e., the
>    unknown attribute and its value, if any) should be ignored.
> I assert that this is the "must ignore" rule for elements and "should
> ignore" for attributes.

I don't see "must" in there anywhere.

> During the time of the most innovation was happening in HTML, from 2. to 4.,
> the must ignore rule was in effect.

It went back to 1.x, during the introduction of <img> and such.
But any implementation that ignored <form> did so at peril of becoming
totally irrelevant.

There's a valuabel pattern of ignoring stuff in there, but it does no
good to call it "must ignore", and to endorse it without
reservation is a disservice to our readership. Noting the downside
is important.

Dan Connolly, W3C

Received on Wednesday, 22 October 2003 11:51:54 UTC