javascript JSONP callback function not defined

Question

(
function restoreURL() {
    function turnLongURL(data) {
        window.location = data.url;
    }

    var shortUrl = window.location.href;

    var url = "http://json-longurl.appspot.com/?url=" + shortUrl + "&callback=turnLongURL";

    var script = document.createElement('script');
    script.setAttribute('src', url);

    document.getElementsByTagName('head')[0].appendChild(script); 
})();

code is above, but the firebug told me, turnLongURL is not defined

why is that?

Quentin · Accepted Answer · 2015-03-11 11:05:10Z

8

JSON-P is added to the document using a script element, so the function call inside it has to reference a function that exists in the global scope.

turnLongURL is limited to the scope of restoreURL since it is defined inside it.

Moving the function declaration to the global scope, or changing it to a function statement thus:

window.turnLongURL = function (data) {

… should make it work.

Remember to account for the possibility of race conditions should multiple JSON-P requests be sent out before the first returns.

edited Mar 11, 2015 at 11:05

answered Dec 24, 2010 at 19:52

Quentin

949k136 gold badges1.3k silver badges1.4k bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Ya Zhuang Over a year ago

it is still not working, and keep saying turnLongURL is not defined... does it make any difference if i am editing a greasemonkey script?

David d C e Freitas Over a year ago

@Quentin What is the best way to account for jsonp race conditions?

James Hibbard Over a year ago

Related? stackoverflow.com/questions/8495825/…

Collectives™ on Stack Overflow

javascript JSONP callback function not defined

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related