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How to callback a function on 404 in JSON ajax request with jQuery?

Asked 2010-03-22T16:31:16.690
22

I want to make an Ajax request with response in JSON. So I made this Ajax request:

$.ajax({
    url: 'http://my_url',
    dataType: "json",
    success: function(data){
      alert('success');
    },
    error: function(data){
      alert('error');
    },
    complete: function(data) {
      alert('complete')
    }})

This code works good but when my url send me a HTTP code 404, no callbacks are used, even the complete callback. After research, it's because my dataType is 'json' so 404 return is HTML and the JSON parsing failed. So no callback.

Have you a solution to call a callback function when a 404 is raised ?

EDIT: complete callback don't call is return is 404. If you want an URL wit 404 you can call : http://twitter.com/status/user_timeline/jksqdlmjmsd.json?count=3&callback=jsonp1269278524295&_=1269278536697 it's with this URL I have my problem.

javascript ajax jquery http-status-code-404
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2 Answers

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$.ajax({
    url: 'http://twitter.com/status/user_timeline/jksqdlmjmsd.json?count=3&callback=jsonp1269278524295&_=1269278536697',
    dataType: "json",
    success: function(data) {
        alert('success');
    },
    error: function(data) {
        alert('error');
    },
    complete: function(xhr, data) {
        if (xhr.status != 0)
             alert('success');
        else
             alert('fail');
    }
})
answered 2010-03-22T16:35:25.853
1

Are you aware that even though the HTTP status is 404, the actual body is valid JSON? For instance, this link has the following JSON:

jsonp1269278524295({"request":"/status/user_timeline/jksqdlmjmsd.json?count=3&callback=jsonp1269278524295&_=1269278536697","error":"Not found"})

As such, you should check if your data has the error property within your normal callback function.

UPDATE: apparently, even though the actual content of the page is valid JSON, the browser (I checked in Firefox) is not executing it, most likely because it is a 404. Because jQuery has to add a script element (because of the cross-domain issue), its JSONP wrapper is never called, and as a consequence, neither are your callbacks.

So, in short, I don't think there is a way to deal with this without manually adding that script element and checking if your pre-defined callback function has been called afterwards.

answered 2010-04-02T19:39:02.117

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