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All Radio Buttons Up Condition needs clarifying - HTML 4.01.

From: Dave J Woolley <DJW@bts.co.uk>
Date: Fri, 14 Apr 2000 11:26:25 +0100
Message-ID: <81E4A2BC03CED111845100104B62AFB58245AE@stagecoach.bts.co.uk>
To: "'www-html@w3.org'" <www-html@w3.org>
Someone has just sent a bug report to the lynx-dev
mailing list claiming that Lynx is at fault for
choosing a default radio button if none are marked
checked in the document.  Reading the HTML 4.01 
specification leaves me confused as to what is really
intended, although all of Amaya, Netscape and IE seem
to start with no buttons down in that case.

The wording of the definition of checked could be read
as logical "if and only if" or as logical implication;
Lynx seems to take the latter view.

The wording of mutual exclusion rule could be interpreted
as "at most one".

More of a problem is that radio buttons are described as
behaving like check boxes, except for the mutual 
exclusion rule.  This would imply that you could restore
an all buttons up state by "clicking" the down button, but
none of the browsers does this.  The overall result is that
the Amaya/Netscape/IE interpretation allows a legal state
for the buttons that can only be restored by resetting the
whole form (or client side scripting).

On real radios, give or take mechanical imperfections, all
buttons up requires one to press a non-latching button
which could equally well really latch, but all up can be
cosmetically better.
Received on Friday, 14 April 2000 06:33:11 GMT

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