jQuery getJSON save result into variable

Question

I use getJSON to request a JSON from my website. It works great, but I need to save the output into another variable, like this:

var myjson= $.getJSON("http://127.0.0.1:8080/horizon-update", function(json) {

                 });

I need to save the result into myjson but it seems this syntax is not correct. Any ideas?

Have a look at [How to return the response from an AJAX call from a function?](http://stackoverflow.com/questions/14220321/how-to-return-the-response-from-an-ajax-call-from-a-function) -- at least it should give you the right idea how to solve the problem. The syntax btw is valid, it just does not do what you want it to. — Felix Kling, Apr 02 '13 at 13:07

score 76 · Accepted Answer · answered Apr 02 '13 at 13:07

76

You can't get value when calling getJSON, only after response.

var myjson;
$.getJSON("http://127.0.0.1:8080/horizon-update", function(json){
    myjson = json;
});

answered Apr 02 '13 at 13:07

webdeveloper

17,174
3
48
47

10

The problem with this is that `var myjson` is not available on the very next line due to timing issues. – John Dvorak Apr 02 '13 at 13:48
2

@JanDvorak Yes, request executes asynchronously, if you need `json` data to proceed, you should call other code after setting `myjson` variable. As solution it could be like 'callbackFuncWithData' from Ravi answer OR just call another function. – webdeveloper Apr 02 '13 at 14:10
1

Once you do that, there's really no reason to keep `myjson` declared outside. Just pass it to the callback as an argument. – John Dvorak Apr 02 '13 at 14:17
@JanDvorak Sometimes it's required, for example when you using client filtering. It depends on your app logic. – webdeveloper Apr 02 '13 at 14:24

Ravi Gadag · Answer 2 · 2013-04-02T13:13:56.763

25

$.getJSon expects a callback functions either you pass it to the callback function or in callback function assign it to global variale.

var globalJsonVar;

    $.getJSON("http://127.0.0.1:8080/horizon-update", function(json){
               //do some thing with json  or assign global variable to incoming json. 
                globalJsonVar=json;
          });

IMO best is to call the callback function. which is nicer to eyes, readability aspects.

$.getJSON("http://127.0.0.1:8080/horizon-update", callbackFuncWithData);

function callbackFuncWithData(data)
{
 // do some thing with data 
}

edited Apr 02 '13 at 13:13

answered Apr 02 '13 at 13:07

Ravi Gadag

15,735
5
57
83

6

i dont think the first solution will works. .getJSON is asynchronous so you wont be able to reach any outside variable. What you need to do is set async:false in low level ajax – lngs Apr 02 '13 at 13:35
3

@lngs: No, it will work. The callback function is a *closure* and has access to all variables defined in higher scopes. You still have to be careful though *when* to access the variable, i.e. you cannot access it immediately after you made the call to `$.getJSON`. In that case you really would have to make a synchronous request. – Felix Kling Apr 02 '13 at 13:36
3

So how could you know when is ajax call finished and how big is response data? You still need to use callback function to do it. – lngs Apr 02 '13 at 14:28
3

Yes, how can you know *when* you can access the data? – bgmCoder Oct 26 '17 at 16:59

jQuery getJSON save result into variable

2 Answers2

Linked