Form event scope

[Martin]

I am writing a javascript object and once complete i will create an
instance of the object to use in my webpage.

Within the object constructor i create a form with a select list in
it, the form is contained in a DIV element.
I want the select list onChange event to call a method of my object.

So the constructor is:

function PanoramaViewer()
{
// code snipped for clarity
// DIV containing form and select list created
// the form HTML is:
// <form name="indexForm"><select name="indexList"
onChange="call_myEvent"></select><br>Auto-hide index:&nbsp;<input
type="checkbox" name="autoHideIndex" checked disabled></form>

this.myEvent=function() { // some script here; };
}

And i create an instance of my object:

var myViewer=new PanoramaViewer();

As you can see i want the select box onChange event to call the
myEvent function.
How can i do this?

onChange="myEvent()" fails as myEvent() is not found in the scope of
the event call.

onChange="myViewer.myEvent()" works as it directly references the
method of the object instance but obviously i don't want to have the
name of an object instance hardcoded into the constructor.
(It works as a hack but isn't really valid).

I've spent a few days searching for ways to have the onChange event
call the instances' myEvent method but found nothing that helps.

Any ideas?

Thanks a lot.

Martin.

PS I can post more detail if needed.

 

[Elegie]

Martin wrote:

Hi Martin,

I've spent a few days searching for ways to have the onChange event
call the instances' myEvent method but found nothing that helps.

There are many ways to do that, Richard Cornford has described an
interesting pattern using closures, check the "associateObjWithEvent"
example in the following article.

<URL:http://www.jibbering.com/faq/faq_notes/closures.html#clObjI>


Kind regards,
Elegie.

 

[Martin]

Martin wrote:

Hi Martin,



There are many ways to do that, Richard Cornford has described an
interesting pattern using closures, check the "associateObjWithEvent"
example in the following article.

<URL:http://www.jibbering.com/faq/faq_notes/closures.html#clObjI>

Kind regards,
Elegie.

Thanks a lot for the link.

It looks like fairly advanced stuff but i'll see what sense i can make
out of it!

Martin.