[whatwg] XML data islands related question
Jukka K. Korpela
jkorpela at cs.tut.fi
Thu Feb 7 10:03:07 PST 2013
2013-02-07 17:55, Randy wrote:
> As far as I'm aware, Data Blocks should be or is part of HTML5. See
> https://developer.mozilla.org/en/docs/Using_XML_Data_Islands_in_Mozilla
> for more info.
It's a somewhat similar concept, but it's about embedded data in
general, not specifically XML data. Moreover, the <xml> element (which
was, as far as I can see, implemented only in IE versions 5 and 6) was
specifically for XML data, implying the idea that the browser parses the
XML data and makes it available in a certain way that you could use with
HTML attributes.
Although <xml> had its merits, it seems to be water under the bridge
now, not supported even by modern versions of IE (though they seem to
have an excuse for a surrogate for broken support: <xml>foobar</xml>
gets ignored, whereas other browsers ignore just the tags and render
foobar).
The current WHATWG HTML document, as well as the W3C HTML5 CR, defines
<script> really as a multi-purpose element:
"The script element allows authors to include dynamic script and data
blocks in their documents."
http://www.whatwg.org/specs/web-apps/current-work/multipage/scripting-1.html#the-script-element
So the name is really a misnomer, though it reflects the most common use
of the element. The content can be plain text, XML text, or text in any
format, as long as you take care of parsing it. In practice, if the type
attribute is set to any value except one of the strings interpreted as
referring to JavaScript, the content is taken just as a block of text
data, made available to client-side scripting but otherwise ignored.
However, browsers do not seem to support using a src attribute then; the
non-script data must be inline, as element content, not fetched from an
external source. I suppose the usual suspects (security considerations)
are to be blaimed. This however means that the technique is not
comparable to <xml>, which allowed external references.
It might be useful to mention explicitly in the spec that browsers do
not generally allow non-script to be specified via the src attribute.
And perhaps the spec should say that this is implementation-dependent
and recommend that such references should be allowed, with due security
considerations.
It's a bit odd that if you wish to set up a standalone application
running in a browser (often called "HTML5 application", without implying
any particular version of HTML5), you can include e.g. scripts and
images in separate files but not plain text or XML data
Yucca
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