javascript variable scope issue undefined

Question

function getData() {
    var photo,
        comment,
        url;

    $.getJSON('http://url.info/verify/settings.php', function (data) {
        photo = data.photoMSG;
        comment = data.commentMSG;
        url = data.photoURL
    });
    console.log(photo); //undefined
    console.log(comment); //undefined
    console.log(url); //undefined
}

I'm getting undefined in console log for all of them... How to get these 3 vars visible outside of getJOSN block? I know this have been asked x100 times, I tried windiw.varName but still the same thing..

Asynchronous calls are *asynchronous*. Add a `console.log('response received now');` into the callback function...! — deceze, Jul 25 '13 at 21:45

score 1 · Accepted Answer · answered Jul 25 '13 at 21:44

It's not a scope issue, it's an asynchronous issue. Everything inside the getJSON handler is asynchronous -- so the console.log calls will usually happen after the variables get assigned. Use an async callback instead:

$.getJSON('http://url.info/verify/settings.php', function (data) {
    photo = data.photoMSG;
    comment = data.commentMSG;
    url = data.photoURL;
    callback(photo, comment, url);
});
function(photo, comment, url) {
    console.log(photo); //undefined
    console.log(comment); //undefined
    console.log(url); //undefined
}

score 0 · Answer 2 · answered Jul 25 '13 at 21:46

0

Because $.getJSON is doing an ajax call, but the code after that is called before the callback within the getJSON is called. So the vars are still undefined. A typical "problem" with asynchronous behaviors.

answered Jul 25 '13 at 21:46

calamari

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javascript variable scope issue undefined

2 Answers2