Re: [Mxquery-xqib] Can't Get b:addEventListener to Work

[Ghislain F. <ghi...@28...>]

Hi Hugh,

> I am trying to make a call to a JavaScript function. I started out with this:
> 
>    b:addEventListener(b:dom()//button[@id='test'], "onclick",
> b:js-call('test'))
> 
> But when I ran it I got:
> 
>> err:XPTY0004 Function Item expected

This is because b:js-call('test') is actually called, and its result is passed to addEventListener (probably not a function). The third parameter should be a function. As of XQuery 3.0, functions are exposed as new kinds of items in the data model, in addition to atomic items and XML nodes.

> So instead I tried wrapping the js-call in a local function:

Yes, I think it's the right approach.

> 
>    declare sequential function local:test()
>    {
>    	b:js-call('test')
>    };
> 
>    b:addEventListener(b:dom()//button[@id='test'], "onclick",
> xs:QName("local:test"))
> 
> Same thing:
> 
>> err:XPTY0004 Function Item expected

This is because xs:QName("local:test") is returning a QName. This actually used to be the way to register events before MXQuery (the engine behind XQIB) supported functions as items.

> So I removed the QName part:
> 
>    declare sequential function local:test()
>    {
>    	b:js-call('test')
>    };
> 
>    b:addEventListener(b:dom()//button[@id='test'], "onclick", local:test)
> 
> But now I get:
> 
>> err:XPDY0002 Context Item not set for step local:italicize

local:test is a step expression, that tries to navigate in an XML tree from the context item, which is not set.

I think that this should work:

   declare sequential function local:test()
   {
   	b:js-call('test')
   };

   b:addEventListener(b:dom()//button[@id='test'], "onclick", local:test#2)

local:test#2 is returning the function named local:test with arity 2 (all listeners have that arity). There is an example on:
http://www.xqib.org/js/OnClickEvent_source.html

I hope this helps?

Kind regards,
Ghislain