Jquery ajax error callback

I need some suggestions here or maybe some explanations. I have a jquery ajax call,

$.ajax({ type: "GET", url: base_url+'/ajax/fetch/counts/', dataType: 'json', data: {}, error: function(xhr, error){ console.debug(xhr); console.debug(error); }, success: display_counts }); 

It's working fine. My success callback fires correctly with response. But, what I noticed is that my error callback is fired every time, even when my call returns success status 200. In the above error callback, I see that object xhr.status is 200.

Can anybody explain what's wrong, or what is happening here? error callback is supposed to fire only when I have 404 or maybe a non-200 response. Are my assumptions correct?

Thanks.

6 Answers

Just an suggestion, try using the $.ajaxSetup() to get the correct error like this:

$(function() { $.ajaxSetup({ error: function(jqXHR, exception) { if (jqXHR.status === 0) { alert('Not connect.\n Verify Network.'); } else if (jqXHR.status == 404) { alert('Requested page not found. [404]'); } else if (jqXHR.status == 500) { alert('Internal Server Error [500].'); } else if (exception === 'parsererror') { alert('Requested JSON parse failed.'); } else if (exception === 'timeout') { alert('Time out error.'); } else if (exception === 'abort') { alert('Ajax request aborted.'); } else { alert('Uncaught Error.\n' + jqXHR.responseText); } } }); }); 

Error callback is called on http errors, but also if JSON parsing on the response fails. This is what's probably happening if response code is 200 but you still are thrown to error callback.

A recent question had similar problem with json jquery requests, try removing surrounding () from your json response.

A few things I can think of:

1. Make sure you have disabled caching by setting cache: false.
2. If you are using Firefox, try using Firebug and the Net tab to monitor the request
3. Don't rely on the browser's JSON parser. I would recommend this one: from the creator of JSON no less

I'm not a jQuery expert, but I know that bwith Prototype.js, the AJAX error handler fires if the request is successful but the success handler causes an an error. Is that the same in jQuery? You could test if this is what's happening by putting the entire contents of display_counts in a try..catch block.

Change dataType from plain/text to html