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Include pattern Strawmen

Possible variations on the include pattern, to resolve issues of accessibility (with empty anchors) and server load (with object):

Toby Inkster's Minimally Verbose Solution

An alternative way of implementing the include pattern in a less verbose, and hopefully more accessible manner:

 <p>We have three branches in <span class="locality" id="ldn">London</span>,
 including our head office in <span class="locality" id="ken">Kensington</span>:</p>
   <li class="adr #ldn">
     <span class="street-address">123 Oxford Street</span>
   <li class="adr #ken #ldn">
     <span class="street-address">5 Kensington High Street</span>
   <li class="adr #ldn">
     <span class="street-address">1 Pall Mall</span>

The order of the space-delimited class attributes should be considered significant -- that is, in <foo class="bar #baz"> the content referred to by #baz is logically included as the last child of the <foo> element, but in <foo class="#baz bar">, it is logically included as the first child. (See below for an example where the included element should occur in the middle of the element content.)

Yes, the hash mark is valid in the class attribute, though rarely used because it won't work with CSS 1 selectors.

If people can find real-life uses of the hash character in existing sites that would conflict with this proposed usage pattern, then perhaps another character could be used. I rather like '@foo', or maybe even a combination such as '@#foo'.

Including data in the middle of an element

Above, the examples show how an element can be logically included as the first or last child of another element. For including data into the middle of an element, we need to be a tiny bit more verbose and insert a dummy element (in this case a <span> element) where the included content should go:

 <p>Our head office is in <span id="ldn" class="locality">London</span> at:
 <p class="adr">
   <span class="street-address">5 Kensington High Street</span><br>
   <span class="#ldn"></span>
   <span class="postal-code">SW7 1AA</span>

problems with ordered ids in class

Two problems:

1. class is an unordered set of values per HTML4. introducing ordering is a non-starter both from a violation of HTML4 spec perspective and likely requiring of rewriting HTML4 parsers to maintain an ordering where they currently don't.

2. inclusion of arbitrary data (#baz) in the class attribute is a documented anti-pattern.

(Unsigned comment by Tantek)

Andy Mabbett

<foo id="birminghamid" class="locality">Birmingham</foo>


<foo class="adr includes-birminghamid">[...]</foo>

Some other possible variants are:

<foo class="adr birminghamid">[...]</foo>


<foo class="adr part-microformat birminghamid">[...]</foo>


<foo class="adr use-birminghamid">[...]</foo>


<foo class="adr uses-birminghamid">[...]</foo>


<foo class="adr include-birminghamid">[...]</foo>


<foo class="adr locality-birminghamid">[...]</foo>


<foo id="birminghamid">Birmingham</foo>
<foo class="adr locality-birminghamid">[...]</foo>

Note: "birminghamid" used for clarity; "birmingham" would be the semantically correct value.

(originally suggested in < et seq.)

problems with arbitrary id values in class attributes

Similar to problems with ordered ids in class, inclusion of arbitrary data (birminghamid) in the class attribute is a documented anti-pattern. (Unsigned comment by Tantek)

  • In this proposal, the class name is not "arbitrary data". In the cited page the use of data in class names is deprecated as "another form of invisible metadata". This proposal involves no more "invisible metadata" than do the existing include patterns; and is semantically logical. Andy Mabbett 00:52, 4 Feb 2008 (PST)

Martin McEvoy

Don't "include" your data, you could perhaps just reference them eg:

<foo id="me" class="fn">Martin McEvoy</foo>
<bar class="me@url"></bar>

parsers instead of replacing data can then just append their data?

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