JSONP callback method is not defined

Question

I'm trying to get a jsonp callback working using jquery within a greasemonkey script. Here's my jquery:

$.ajax({
    url: "http://mydomain.com/MyWebService?callback=?",
    data: { authkey: "temphash" },
    type: "get",
    dataType: "json",
    cache: false,
    success: function(data) {
        console.log(data);
    }
});

in my webservice (asp.net) I'm returning the response with a content type of application/javascript. The response the server is actually sending back is:

jsonp1276109314602({"message":"I'm getting tired of this not working"})

The jsonp1276109314602 method name is being randomly generated by jquery, and I'm grabbing it with Request.QueryString["callback"]

However my success function is never called and the firebug console gives me an error saying jsonp1276109314602 is not defined.

What am I doing wrong?

NOTE I'm making this call from a greasemonkey script on a craigslist page. It's a cross-domain request, but I can see the request is actually making it to the server and returning a good response, but for whatever reason the registered callback that jquery creates appears to not exist when the response comes back. It works fine if I run the script in the firebug console from the craigslist page, but not when it's run from the greasemonkey script.

Are you embedding jQuery in the GreaseMonkey script or loading it separately? — James, Jun 09 '10 at 19:18
... Or, is jQuery already available on the page that you're enhancing? — James, Jun 09 '10 at 19:19
you can solve this problem using jsonp.Please follow the link below. This site also contains demo code. [http://www.onlinesolutionsdevelopment.com/blog/web-development/javascript/jsonp-example/](http://www.onlinesolutionsdevelopment.com/blog/web-development/javascript/jsonp-example/) Hope this can solve your problem. — , May 21 '12 at 10:17

score 3 · Answer 1 · answered Jun 09 '10 at 20:18

Have you already tried:

$.ajax({
    url: "http://mydomain.com/MyWebService",
    data: { authkey: "temphash" },
    type: "get",
    dataType: "jsonp",
    cache: false,
    success: function(data) {
        console.log(data);
    }
});

From docs:

"jsonp": Loads in a JSON block using JSONP. Will add an extra "?callback=?" to the end of your URL to specify the callback.

I haven't examined jQuery's source code but it's possible that the callback function isn't created unless you specify jsonp for the dataType option.

score 2 · Accepted Answer · edited May 23 '17 at 12:01

2

It turns out that you have to do some extra monkeying around (pun intended) to get it to work inside a greasemonkey script.

The long answer can be found here: jQuery.getJSON inside a greasemonkey user script.

The short answer is to ditch the JSONP approach and include this in your script:

// @require http://courses.ischool.berkeley.edu/i290-4/f09/resources/gm_jq_xhr.js

Not sure I understand it all, but nonetheless it works like a champ and I'm able to make cross domain requests from my script.

edited May 23 '17 at 12:01

Community

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answered Jun 10 '10 at 15:51

Micah

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If you're interested in how the `gm_jq_xhr.js` script works, you can read [an explanation](http://ryangreenberg.com/archives/2010/03/greasemonkey_jquery.php) I wrote. – Ryan Aug 29 '10 at 02:19

score 1 · Answer 3 · answered Nov 05 '10 at 17:17

1

I think you're supposed to use 'jsonpCallbackString' instead of 'success'.

http://api.jquery.com/jQuery.ajax/

answered Nov 05 '10 at 17:17

tkane2000

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1

JSONP callback method is not defined

3 Answers3