Forum: Rails Spinoffs (closed, excessive spam) JSONP & Prototype.js

C5e908acf2a15f7abd9184ca4e6e3072?d=identicon&s=25 Ron Derksen (Guest)
on 2008-06-17 14:22
(Received via mailing list)
Hi list,

I've been looking for a JSONP implementation in Prototype, but can't
seem to find any yet. I came across something from a guy called Cody
Swann, but that didn't seem to work, and his website seems to have
disappeared. I tried to come up with a nice, integrated way to do it
myself, but I'm not sure that it's possible to use the default
Prototype Ajax way of doing things. Does anyone have something ready
to go, or can someone give me some pointers on how to best implement

Ron Derksen
4dae3b057d62f103f56d2c5d58007a08?d=identicon&s=25 Ryan Gahl (Guest)
on 2008-06-17 16:00
(Received via mailing list)
All JSONP is, is an endpoint that returns javascript that is a call to a
named function on your page, usually passing the resultant processed
data as
a JSON parameter to said function. Some JSONP endpoints will have a
name for that callback function, and some allow you to specify the name
that function in your request parameters (usually via the query string
JSONP is really designed for consumption via script tags, not Ajax).

There is nothing special you have to do on the client side other than
have a
named function available (which again should match what the JSONP
is returning, or what you pass in to a configurable JSONP endpoint), and
allow your XHR layer to eval javascript (which Prototype does; see:

If you're consuming a JSONP endpoint with Ajax, though, you're kind of
defeating one of the main purposes of JSONP. XHR, of course, requires
you follow SOP (same origin policy), which means the XHR calls need to
go to
the same domain as the current page. JSONP is really designed to be
via script tags, thus is a cross domain scripting method primarily. If
you're building the backend yourself and aren't building a public
API where you want to enable people to use script tags to make calls
domain... then for all intents and purposes you really don't need JSONP.

So anyway, the answer is you don't need to do anything special, just
have a
named function available (at the global level) in your page, that the
returned javascript can call into.

On 6/17/08, Ron Derksen <> wrote:
> to go, or can someone give me some pointers on how to best implement
> it?
> Cheers,
> Ron Derksen
> >

Ryan Gahl
Manager, Senior Software Engineer
Nth Penguin, LLC
-- /
Future Home of the World's First Complete Web Platform
Inquire: 1-920-574-2218
LinkedIn Profile:
F1fcf834ddad415f60d29c87cc10d4d4?d=identicon&s=25 kangax (Guest)
on 2008-06-17 18:40
(Received via mailing list)
I've been playing with JSONP some time ago. Take a look at:

- kangax
This topic is locked and can not be replied to.