W3C home > Mailing lists > Public > www-forms@w3.org > October 2005

RE: How can I send messages between XForms and HTML

From: Mark Birbeck <mark.birbeck@x-port.net>
Date: Mon, 3 Oct 2005 14:59:33 +0100
Message-ID: <CB29040C-CE1E-41D9-841D-7F88F990C461@s15.mail.x-port.net>
To: "'Sergey Shebanin'" <splash@rulogic.ru>
Cc: <www-forms@w3.org>

Hi Sergey,

>	In IE (FormsPlayer) I can catch only standard event (defined in W3C
>	Recommendation) with
>	<script for="object-id" event="xforms-event" type="text/javascript">
>	But I still cann't catch any user defined events fired with
>	<xforms:dispatch .../>

That's right. It's not a good technique to use, to be honest, since what's
happening is we are mapping 'proper' DOM 2 Events as generated by our XForms
processor into 'old-style' events as used by IE. In the case of <script> IE
can only register for known events.

What you can do instead, is to create a DOM 2 Events handler object and then
set its handler object to point to a JavaScript function:

  var theListener = this.document.getFeature("Events.listener", "2.0");
  theListener.handler = this.handleDOM2Event;

  function handleDOM2Event(evt)
  {
    ...
  }

Once you have this handler object you can attach it to the correct target:

  oTarget.addEventListener("my-event", theListener, false);

This all amounts to doing the same as Alex's suggestion, which was:

  document.addEventListener("xforms-refresh", function(){ jsfunc(); },
false);

The reason for the difference is that the DOM 2 Events specification defines
the second parameter to addEventListener() as being a listener object.
However, most implementations allow a JavaScript function to be passed in
this position, and although this is in ECMAScript bindings section of the
spec, there is nowhere that we can find that says that there is some
implicit cast going on. So until we resolve this we decided to create an
explicit listener object, and then wire it up to point to the function you
want.


>	Also when I call
>
document.getElementById('some-xforms-trigger').fireEvent('DOMActivate')
>	I see error message.
>	Can anybody explain how to interact XForms and JavaScript in IE
>	(FormsPlayer)

As Alex says, you need to use the standard DOM 2 Events techniques:

> Sending is likewise done with createEvent() and dispatchEvent().

and we have added stuff to the IE DOM so that you can use these standards.
To illustrate, here's a snippet from one of the clock demos:

  <script type="text/javascript">
    function fnSetTimeoutFrequency(nSecs)
    {
      setTimeout(fnTimeout, nSecs * 1000);
    }

    function fnTimeout()
    {
      var evt = document.createEvent("Event");
      var oEvtList = document.getElementById("event-list");

      evt.initEvent("my-timeout", false, false);
      oEvtList.dispatchEvent(evt);

      /*
       * Set the next timeout for one seconds time
       */

      fnSetTimeoutFrequency(10);
      return;
    }
  </script>

  <xf:group id="event-list">
    <xf:action ev:event="my-timeout">
      <xf:setvalue ref="instance('i')/now" value="now()" />
    </xf:action>
  </xf:group>

Note that all of these techniques are only available to you on one of our
XForms elements, since we are co-existing with the normal IE DOM. (By that I
mean that 'oTarget' cannot be an HTML element.)

Regards,

Mark

Mark Birbeck
CEO
x-port.net Ltd.

e: Mark.Birbeck@x-port.net
t: +44 (0) 20 7689 9232
w: http://www.formsPlayer.com/
b: http://internet-apps.blogspot.com/

Download our XForms processor from
http://www.formsPlayer.com/
Received on Monday, 3 October 2005 14:00:19 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Saturday, 10 March 2012 06:22:01 GMT