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RE: Why Doesn't IE5 use the DTD to Validate?

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Hi Chris,

<YourComment>
> Structural integrity is the responsibility of the emitter.

Yes, but

a) they will only take that responsibility if it buys them something
b) if it seems to usually work anyway without validating, they don't
think it buys them anything
</YourComment>

<Reply>
Simple scenario: The emitter sends a document having its structural
integrity not valid. This document has a Style sheet associated to it that
has the premise that the document has the right structure. The receiver
tries to render the document in a browser. The browser uses a non validating
parser but can nevertheless parse the document because, from a parsing point
of view, everything is there for the task. So the parse is able to build a
parse tree. The style sheet engine tries to apply its script on this parse
tree and fail because some elements are positioned at the right place.
result, the document is not displayed properly.

What is the incentive to the producer to have its document validated before
publishing? simply that it could be displayed and that is true for all
cases. So, like I said, the responsibility to have the document structurally
valid is the emitter responsibility.
</reply>

<YourComment>
> However, when
> electronic commerce transactions are the kind of operation done.
Validation
> may be necessary for the receiver to be sure that the transaction is OK,
so
> in that case a double check may be necessary A) at the emitter end and the
> receiver end.

Electronic commerce is just one example where validation must be
insisted upon. It is not the only example, and some examples include
document display.

The thing to remember is, there is more being built using Web
specifications than just the typical, joe passive consumer taking a
break from watching the television sort of "browsing". There are other
sorts of browsing and there are other sorts of document transfer and
display and other usage scenarios.

If, in the documentation for the aircraft I am flying on or the nuclear
plant that generates my electricity or the maintenence manual for a
blood gas analyser whose results my doctor is depending on, the document
is invalid because

<!ATTLIST failure-condition severity
(silent-redundant|minor|fixat6months|fixin24hours|urgent|emergency|criticalh
alt)
#REQUIRED>

and the required severity attribute is missing, and the style sheet has

diagnostic fault failure-condition[severity=criticalhalt]:before
  {content: "Shut this thing down NOW before she blows"'
   color: red; background: black;
   font-size: 8em; text-decoration: blink }

I certainly want to know about it and I want a validation check each
time the document is viewed.
</YourComment>

<Reply>
And just to take your scenario. The receiving browser equipped with a
validation parser detect structure error, the document is not displayed and
the nuclear central creates a huge ecological disaster. If the document is
not valid a validating parser cannot fix the situation. It can just tell the
nuclear operator "run for your life dear". And a browser using a non
validating parser will just end up with the same result :-)))
</Reply>

<YourComment>
> However, the interpreter in that case is probably not a
> browser but an other kind of application.

All browsers are equal, but some are more equal than others. And, some
things are more important than electronic commerce.
</YourComment>

<Reply>
Sorry Chris, I don't follow you there. I guess you just got me with an April
foul :-)))
</Reply>

Regards
Didier PH Martin
mailto:martind@xxxxxxxxxxxxx
http://www.netfolder.com


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