Re: My own taxonomic listing

On Fri, Jun 06, 2003 at 12:55:01PM -0400, John Cowan wrote:
> In order for HTML to be also XML, the following rules must be satisfied:
>
0) All element and attribute names must be in lowercase.

This keeps an awful lot of pages from being legal XHTML; many people,
myself included, used to use uppercase to make the tags stand out
from the surrounding text.

> 1) All attribute values must be in quotation marks;
1a) All attributes must have values.  For instance,

        <input type="checkbox" checked>

is legal HTML, but not legal XHTML.    You have to specify a value
for the "checked" attribute, even though it's just a Boolean flag
(it's either there or it isn't).  Rather than use something like
"yes" or "true" or "on" for all of these, the XHTML 1.0 standard specifies
that the value is the same as the name of the attribute, so the XHTML
form of the above is

        <input type="checkbox" checked="checked"/>

> 2) No stray < or & characters are allowed (use &lt; and &amp; instead);
>
> 3) All start-tags must either have end-tags, or else a / must appear just
> before the closing > of the tag (preceding it with a space avoids problems
> in old browsers);
>
> 4) No overlapping tags are allowed;
>
> 5) All entity references like "&aacute;" must end with semicolons.
-Mark