Hi again,
I will just mention that if you start using logic objects and such on
the client side where the handler is a "method" of the logic object,
then this becomes more problematic, since you have two different
things you want to do with "this": Refer to the logic instance, and
refer to the 'json' object. Not a problem if you don't intend to do
that, but if you do, Prototype makes it easy to both preserve "this"
AND pass an extra parameter to your event handler after the event
object: Function.bindAsEventListener[1]. It's pretty specialized,
you don't find you need it much, but if you want to set up an event
handler and pass it extra parameters, this is what you need.
[1] http://www.prototypejs.org/api/function/bindaseventlistener
Assuming we're operating in the context where you have 'json' and
where "this" currently refers to your logic instance, here's how you
hook it up:
$('myelement').observe('click',
this.clickHandler.bindAsEventListener(this, json));
When clickHandler() gets triggered, "this" will be the logic instance,
the first parameter will be the event object, and the second parameter
will be 'json':
function clickHandler(evt, json)
{
// Get the glarb from json
var glarb = json.glarb;
// Do something with it using another "method" of this instance
this.doSomething(glarb);
}
FWIW,
--
T.J. Crowder
tj / crowder software / com
On Oct 17, 8:51 pm, "suki rosen" <[EMAIL PROTECTED]> wrote:
> that's great. thanks - I'm glad I was on the right track there. This seems
> very useful for dealing with ajax data.
>
> On Fri, Oct 17, 2008 at 3:33 PM, T.J. Crowder <[EMAIL PROTECTED]>wrote:
>
>
>
> > Hi,
>
> > > Is this what bind() is for? Can I *bind* my json object to a function
> > > that refers back to the original object?
>
> > FWIW, I'd say it's a clever use of bind(). The question of whether
> > it's what bind() is *for* is kind of moot. (I'd say, on balance, yes
> > it is -- bind() is for binding functions to objects [or maybe vice-
> > versa]. This isn't the way you normally see it used, but that's a
> > different matter...) So yeah, if you don't need the context ("this")
> > for some other purpose, no reason you can't do it like that.
>
> > Once you're at the point where you have your JSON data turned back
> > into an object (I'll call it 'json'), hooking up an event handler
> > would look like this:
>
> > $('someElement').observe('click', clickHandler.bind(json));
>
> > Then when someone clicks that element and your clickHandler() function
> > is called, you have access to 'json' within your function as "this":
>
> > function clickHandler(evt)
> > {
> > // Get the blarg from json:
> > var blarg = this.blarg;
> > }
>
> > I don't think I've seen anyone do quite that thing before, but it
> > seems like a perfectly valid use of bind().
>
> > HTH,
> > --
> > T.J. Crowder
> > tj / crowder software / com
>
> > On Oct 17, 7:49 pm, pancakes <[EMAIL PROTECTED]> wrote:
> > > I have searched around for some answer to this and I have a feeling I
> > > could make it work using bind(), but I'm not sure - I'm not exactly
> > > understanding the examples and explanations in regard to my example.
>
> > > I am returning a json object from the server/ajax. I am building some
> > > page elements using the json object. I'd like to allow the user to
> > > click on the newly updated content and have that click update a
> > > different part of the page. But I'd like to reference the original
> > > json object, rather than pass all of the relevant information in the
> > > onclick.
>
> > > Is this what bind() is for? Can I *bind* my json object to a function
> > > that refers back to the original object?
>
>
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