getJSON返回200但出现错误

Question

I am trying to write some simple Javascript to load a JSON payload from a URL.

I know I have CORS issues, and for the moment I'm fine with that. I can disable chrome's check.

The problem I have is that I get back a 200 OK response, but also an error and I don't understand why.

 var urlAddress = "https://light-ratio-149809.appspot.com/ESI-OrgUnitService?jsoncallback=?"; $.getJSON(urlAddress, { format: "json" }) .always(function( jqXHR, textStatus, errorThrown ) { console.log("reponse textStatus["+textStatus+"] errorThrown["+errorThrown+"] [" + jqXHR.responseText + "]"); }) .done(function(data) { console.log("success"); }); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> 

Can someone please tell me where I'm going wrong?

If I use this JSON payload, it works.

https://gist.githubusercontent.com/Miserlou/c5cd8364bf9b2420bb29/raw/2bf258763cdddd704f8ffd3ea9a3e81d25e2c6f6/cities.json

The error looks to be a parse error.

reponse textStatus[parsererror] errorThrown[Error: jQuery331004379421802427674_1551456238952 was not called] [undefined]

Answer 1

The parseError is because jQuery thinks you're expecting a JSONP response (ie some executable Javascript), not just JSON data. It thinks that because you added the jsonCallback querystring parameter to the URL.

Once you remove that, it goes back to expecting regular JSON (which is what the endpoint returns), but is then defeated by the server's CORS restrictions.

You can't get round CORS by pretending you want to receive JSONP when that's not actually what the server is returning. I suggest you find out whether this server does in fact have a JSONP endpoint, or whether your app can be added as an allowed CORS client.