fyi - this works great! In my case, I am simply looking for a
reference to the attributes of the json object that was returned - but
thanks for the comments.
here's how I used this technique (a simplified version where we
populate an img tag with a thumbnail - which can populate another
block with the same thumb when clicked)
function clickHandler(evt){
$('imgtag_we_want_to_populate').src = this.thumb;
}
function stateChanged(response){
var json = response.responseText.evalJSON();
for (i=0; i< {json_length_variable} ;i++){
var clickable_thumbnail = 'id_of_clickable_element'+i;
var response_user_thumb = json['message'][i].thumb;
$(clickable_thumbnail).innerHTML = '<img src="'+
response_user_thumb +'">';
// in the callback, I'm passing a reference to the
specific row being dealt with
$(clickable_thumbnail).observe('click',
clickHandler.bind(json['message'][i]));
}
}
On Oct 17, 4:44 pm, "T.J. Crowder" <[EMAIL PROTECTED]> wrote:
> 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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