jQuery won't parse my JSON from AJAX query

Asked 2008-10-30T09:47:17.470

I'm having difficulty parsing some JSON data returned from my server using jQuery.ajax()

To perform the AJAX I'm using:

$.ajax({
  url: myUrl,
  cache: false,
  dataType: "json",
  success: function(data){
    ...
  },
  error: function(e, xhr){
    ...
  }
});

And if I return an array of items then it works fine:

[ { title: "One", key: "1" }, { title: "Two", key: "2" } ]

The success function is called and receives the correct object.

However, when I'm trying to return a single object:

{ title: "One", key: "1" }

The error function is called and xhr contains 'parsererror'. I've tried wrapping the JSON in parenthesis on the server before sending it down the wire, but it makes no difference. Yet if I paste the content into a string in Javascript and then use the eval() function, it evaluates it perfectly.

Any ideas what I'm doing wrong?

Anthony

jquery ajax json

Edit Report

5 Answers

Is your server sending data as Content-Type "*/json"? If not, modify the response headers accordingly. Sending "application/json" would be fine, for example.

answered 2008-10-30T10:29:13.347

I had this issue and for a bit I used

eval('('+data+')')

to get the data returned in an object. but then later had other issues getting a 'missing ) in parenthetical' error and found out that jQuery has a function specifically for evaluating a string for a json structure:

$.parseJSON(data)

should do the trick. This is in addition to having your json string in the proper format of course..

answered 2010-12-16T21:55:52.180

I had a similar problem to this where Firefox 3.5 worked fine and parsed my JSON data but Firefox 3.0.6 returned a parseerror. Turned out it was a blank space at the start of the JSON that caused Firefox 3.0.6 to throw an error. Removing the blank space fixed it

answered 2010-01-27T11:52:03.053

If jQuery's error handler is being called and the XHR object contains "parser error", that's probably a parser error coming back from the server.

Is your multiple result scenario when you call the service without a parameter, but it's breaking when you try to supply a parameter to retrieve the single record?

What backend are you returning this from?

On ASMX services, for example, that's often the case when parameters are supplied to jQuery as a JSON object instead of a JSON string. If you provide jQuery an actual JSON object for its "data" parameter, it will serialize that into standard & delimited k,v pairs instead of sending it as JSON.

answered 2008-11-28T04:48:05.977

In a ColdFusion environment, one thing that will cause an error, even with well-formed JSON, is having Enable Request Debugging Output turned on in the ColdFusion Administrator (under Debugging & Logging > Debug Output Settings). Debugging information will be returned with the JSON data and will thus make it invalid.

answered 2011-04-04T17:40:16.197

jQuery won't parse my JSON from AJAX query

5 Answers

Your Answer