[whatwg] XML data islands related question

Ian Hickson ian at hixie.ch
Mon Aug 5 16:27:41 PDT 2013

On Thu, 7 Feb 2013, Neerja Anand wrote:
> Hello - it appears that XML data islands (originally created by 
> Microsoft) have been discontinued in the newer browsers. We wanted to 
> request they could be supported as an addon/plugin into the browser if 
> not incorporated into the browser by default. We understand that this 
> was a Microsoft only feature but they are extremely helpful to our 
> business and their discontinuation would highly affect our business. Our 
> request is to make them as an HTML5 standard, so all browsers would then 
> have to support this feature. This would make the life of us developers 
> much easier. We are not asking for Microsoft's version of XML data 
> islands specifically, but would want this feature as a standard in some 
> version. We noticed there is something new called Data Block which may 
> be similar to XML data islands, but couldn't find much information on it 
> to proceed. If you know of Data Blocks being an alternative to XML data 
> islands, then if you could provide some documentation or point us to the 
> location where we can get more information (with examples on how to use 
> them) that would be very helpful as well.

Could you elaborate on the use case? Why do you use them / want to use 
them? What are they for?

On Thu, 7 Feb 2013, Mat Carey wrote:
> I'm not particularly active on WHATWG but the general approach seems to 
> be that if you have a good idea you should go and create it, show that 
> it works and then bring it to WHATWG for a wider adoption.

That certainly is a solid way of approaching things.

On Thu, 7 Feb 2013, 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.

On Thu, 7 Feb 2013, Jukka K. Korpela wrote:
> [...] 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. 

The spec seems pretty clear about this:

# When used to include data blocks (as opposed to scripts), the data must 
# be embedded inline, the format of the data must be given using the type 
# attribute, the src attribute must not be specified, and the contents of 
# the script element must conform to the requirements defined for the 
# format used.

(This paragraph of <script> section.)

> And perhaps the spec should say that this is implementation-dependent 
> and recommend that such references should be allowed, with due security 
> considerations.

Implementation-dependent behaviour is, on the whole, just a source of 
confusion for authors, so I'd rather not do that.

You can just use XHR, instead.

> 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

Why can't you put plain text or XML data in other files? So long as 
everything is same origin, you can read anything you want via XHR.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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