How to handle an ActiveX event in Javascript

This is somewhat of a follow-up to an answer here.

I have a custom ActiveX control that is raising an event ("ReceiveMessage" with a "msg" parameter) that needs to be handled by Javascript in the web browser. Historically we've been able to use the following IE-only syntax to accomplish this on different projects:

function MyControl::ReceiveMessage(msg)
{
   alert(msg);
}

However, when inside a layout in which the control is buried, the Javascript cannot find the control. Specifically, if we put this into a plain HTML page it works fine, but if we put it into an ASPX page wrapped by the <Form> tag, we get a "MyControl is undefined" error. We've tried variations on the following:

var GetControl = document.getElementById("MyControl");
function GetControl::ReceiveMessage(msg)
{
   alert(msg);
}

... but it results in the Javascript error "GetControl is undefined."

What is the proper way to handle an event being sent from an ActiveX control? Right now we're only interested in getting this working in IE. This has to be a custom ActiveX control for what we're doing.

Thanks.

javascript events activex

Edit Report

I think that the MyControl::ReceiveMessage example does not work because the ActiveX control is being exposed with a different name or in a different scope.

With the example GetControl::ReceiveMessage, I believe that the function definition is being parsed before the GetControl reference is being set, thus it does not refer to a valid object and cannot bind the function to the object.

I would attack this problem by using the MS script debugger and trying to determine if a default reference for the control exists with a different name or in a different scope (possibly as a child of the form). If you can determine the correct reference for the control, you should be able to bind the function properly with the Automagic :: method that the MSDN article specifies.

One more thought, the reference may be based on the name of the object and not the ID, so try setting both :)

answered 2008-10-07T00:45:57.297

How to handle an ActiveX event in Javascript

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