CODEWITHSUNDEEP
javascript
adit
adit

Reputation: 33644

variable scoping in javascript

My code is as follows:

jQuery(document).ready(function() {
        var pic = 0;
        FB.init({appId: '1355701231239404', status: true, cookie: true, xfbml: true});
        FB.getLoginStatus(function(response) {
        if (response.session) {
            pic = "http://graph.facebook.com/" + response.session.uid + "/picture";     
            alert(pic);
         } else {
            window.location = "index.php"
         }       
        });

    });
    </script>

The issue is that the pic inside my if statement has a different scope with the one I declared above? Why and how do I make them the same?

What I want is to use this var pic (the one that has been assigned by the if statement) inside the body of my html. I will have another script inside the body, a document.write that uses this pic variable.. as of now when I do a document.write it always gives me 0, as if it's not assigned inside the if statement

Upvotes: 1

Views: 95

Answers (2)

Daniel Earwicker
Daniel Earwicker

Reputation: 116654

But there is only one pic in that snippet. So the issue you describe doesn't exist. What problem are you experiencing? How does the code misbehave compared with what you expect?

Update

Okay, your actual problem is that you're expecting pic to be updated so you can use the value of it elsewhere. But consider:

FB.getLoginStatus(function(response) { ... });

The reason that function executes a callback, instead of returning response as a return value, is because it is asynchronous. It make take a while to get the response, and so it doesn't execute the callback immediately. So your other piece of code is probably executing before that happens, i.e. before pic has been properly initialised with a value.

Upvotes: 1

Quentin
Quentin

Reputation: 943142

The issue is that the pic inside my if statement has a different scope

No, it isn't. JavaScript scope is by function. var pic = 0; scopes pic to the anonymous function passed to ready(). The anonymous function passed to getLoginStatus() doesn't use var at all, so the scope of pic there is the same.

(Since you didn't say what outcome you got or what outcome you were expecting, it is hard to say what the solution to your problem actually is)

Upvotes: 3

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