Re: m-dashes

Chris Croome <chris@atomism.demon.co.uk> wrote:
>I've just noticed that the Lie and Bos book on CSS
>(www.awl.com/css/) has this under the list of special
>characters:
>
>&mdash;
>
>However NN4 does not seem to support it :-(
>
>Should there be something in the WAI check list advising
>people not to use things like &#151;?

	See the section on entities, and subsections on character
references, in the HTML 4.0 specification.  The value which follows
the &# can be decimal digits for a decimal value, or an x followed
by hexadecimal digits for a hexadecimal value, corresponding to a
Unicode character.  Thus, the numeric character reference for
&mdash; is &#8212; or &#x2014;.

	The Unicode values correspond to the US-ASCII values through
decimal 127, and ISO-8859-1 values through decimal 255.  The decimal
values 127 through 159 are invalid in HTML.  The major GUI browsers
invalidly treat character references in that range as Windows charset
(e.g., ISO-8859-1-Windows-3.1-Latin-1, a.k.a, windows-1252) values.
You not only should discourage their use, but the vendors of those
browsers should be encouraged to respect the HTML specifications.
The HTML 4.0 specs include named character references (e.g., mdash,
ndash, lsquo, rsquo) for fancy dashes, quotation marks, spaces, etc.,
in that Windows codepage range, and, of course, all have valid Unicode
numeric character references which could and should be used instead of
the invalid ones.

	For accessibility reasons, Lynx v2.7.2 "handles" those invalid
character references (e.g., substitutes ASCII dashes or quotation marks
for the intended fancy ones) as is does the valid named and numeric
character references, but (for better or worse :) this "acceptance of
invalidity" is not done in the current Lynx development code that will
become v2.8.

				Fote

=========================================================================
 Foteos Macrides            Worcester Foundation for Biomedical Research
 MACRIDES@SCI.WFBR.EDU         222 Maple Avenue, Shrewsbury, MA 01545
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Received on Friday, 6 February 1998 21:32:44 UTC