How to use WhateverOrigin to circumvent same-domain policy

Question

I went to whateverorigin.com to generate this line of javascript:

$.getJSON('http://whateverorigin.org/get?url=' +
  encodeURIComponent('http://google.com') + 
  '&callback=?', function(data){ alert(data.contents); });

I put that in place of the XMLHttpRequest I was using before, and nothing happens. Chrome says I have an Uncaught Reference Error: jQuery110201568311753217131_1395117728011 is not defined. I must not be setting everything up right, what else do I need to do besides put that line with the relevant url in my JavaScript?

@aquemini : for same domain you don't need to use '&callback=?', even though if use that, you must resend same callback with your response — Laxmikant Ratnaparkhi, Mar 18 '14 at 04:55
Interestingly, you can run that code on page and it works! :-) — go-oleg, Mar 18 '14 at 04:55
Can you make a [jsfiddle](http://jsfiddle.net) that recreates your problem, as http://jsfiddle.net/968TS/ the basic setup in this fiddle shows it working — Patrick Evans, Mar 18 '14 at 04:56
@PatrickEvans http://jsfiddle.net/968TS/4/ i think that captures it — aquemini, Mar 18 '14 at 05:02
@aquemini - this variation seems to work: http://jsfiddle.net/jfriend00/HPTFm/. You have to include "callback=?" with `$.getJSON()` for it to know that you want to use JSONP which is required for cross origin. — jfriend00, Mar 18 '14 at 05:14
@jfriend00 that does work in fiddle, but not in the browser. when i add "callback=?" back in, i get the uncaught reference error i mentioned in the original post. any reason that could be? — aquemini, Mar 18 '14 at 05:18
@aquemini - then something else (that you haven't disclosed to us) is wrong with your regular page. jQuery knows how to process that request if you set it up right. — jfriend00, Mar 18 '14 at 05:19
@jfriend00 here's the fiddle with my exact code: http://jsfiddle.net/HPTFm/7/...same problem, works in fiddle, not in my chrome extension. i even put an "alert(team)" right before the call to .getJSON and that works fine in Chrome — aquemini, Mar 18 '14 at 05:23
Hmmm, you didn't say until just now that this is a Chrome extension. I wonder what is different about that environment? Perhaps it has a different global variable space and thus the JSONP callback can't find the global function it's supposed to call? — jfriend00, Mar 18 '14 at 05:24

score 1 · Accepted Answer · edited May 23 '17 at 10:31

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The issue is that the Chrome extension has it's own sandboxed global variables and thus the global callback function that a JSONP request uses doesn't work when made from a Chrome extension.

See JSONP request in chrome extension, callback function doesn't exist? and JSONP communication in a Google Chrome extension and Using jQuery.getJSON in Chrome Extension for further details. This question is probably a dup of that one.

If you search Google for "JSONP Chrome Extension", you find many discussions of this issue with several different resolutions depending upon the exact circumstances.

edited May 23 '17 at 10:31

Community

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answered Mar 18 '14 at 05:27

jfriend00

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@aquemini - yeah, the missing piece of info was that you're in a Chrome Extension. The Google search was quite simple once we knew that to be the relevant difference. – jfriend00 Mar 18 '14 at 05:33

How to use WhateverOrigin to circumvent same-domain policy

1 Answers1