$.getJSON not parsing object in callback

Question

I have a simple getJson request:

$.getJSON('JsonTest', function(o) {
alert(o.Test);
});

It works, but in Firebug the "o" never gets turned into an object, but stays a string:

{"Test":"Hello"}

If I do an

eval('(' + o + ')')

It gets evaluated fine, the only thing I can think of is that there's some sort of cross site scripting problem, but I'm running everything on my development machine, the JsonTest is off of localhost:port/Controller/JsonTest

Any ideas as to what could be wrong? How do I check to see whether or not it is a cross site issue? Any other ideas?

Answer 1

Is it possible that your JsonTest service is "double escaping" the json that gets sent back? As in:

"{\"Test\":\"Hello\"}"

Since you have firebug, can you take a look at the response and paste the raw text that it shows?

If your service method returns a string, and you are doing your own serialization, then this is definitely the case. I ran in to this recently. Anyway, with the "double quoted" (or double wrapped, double escaped, whatever you want to call it) json coming back, $.getJSON() only eval()'s it once, turning "{\"Test\":\"Hello\"}" into {"Test":"Hello"}, which does indeed still require an additional eval().

Also, don't use eval(). Use JSON.parse(). You can include json2.js from http://json.org/, and JSON.parse() will either use the browser's native json parsing abilities, or fall back on json2.js if the browser doesn't do it natively.