Re: [Xsltforms-support] Change instance via JavaScript?

[C. M. Sperberg-M. <cm...@bl...>]

On Nov 6, 2011, at 3:41 PM, Alain Couthures wrote:
>> ...
> Modifying an instance with Javascript instructions is always problematic 
> because of dependencies to be set for refresh. It could also be very 
> specific of a version of en implementation...
> 
> Maybe the best way would be to just define an extension for submission: 
> instead of "http:" or "file:", "javascript:" could be used to retrieve a 
> string from a Javascript instruction.
> 
> You could then externally activate a submit action for it.
> 
> What do you think?


Well, I don't know about the original poster, but I think you've just 
explained to me how to handle a problem I was having without a
trip to the server.  Thank you!

However, when I try to put this idea into practice, I encounter 
a simple practical difficulty.  I want to use Javascript to manipulate a
string in the document, so I write a function called, say,
manipulate_string, which takes a string as argument and returns
a string as its result.

I can write a submission element that specifies a call to this
function as the resource, and I can even specify the argument
(which I have placed in an instance document for the purpose),
thus:

       <xf:submission id="hackstring"
	 method="get"
	 ref="instance('stringhack')/s"
	 replace="text"
	 targetref="instance('stringhack')/s"
	 >
	 <xf:resource
	     value="concat('javascript:manipulate_string(&quot;', instance('stringhack')/s, '&quot;)')"
	     />
       </xf:submission>

But before submission, XForms appends "?s=" and the value of the
XPath expression in the 'ref' attribute, which has the effect that 
the Javascript call is not recognized so my function never executes.

Is there a way around this problem?

-- 
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* C. M. Sperberg-McQueen, Black Mesa Technologies LLC
* http://www.blackmesatech.com 
* http://cmsmcq.com/mib                 
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