How do I specify more arguments to be passed to a jsonp callback function?

For example, I'm trying to grab youtube video data:

;alt=json-in-script&callback=youtubeFeedCallback

The javascript callback function that will be called is youtubeFeedCallback and it contains only one argument when called.

As of now the function would be something like this,

function youtubFeedCallback(response) {
...
}

What I would like to be able to do is pass a second argument like this,

function youtubeFeedCallback(response, divId) {
...
}

Is this possible to do. I've tried looking everywhere online and couldn't find anything. Thanks!

How do I specify more arguments to be passed to a jsonp callback function?

For example, I'm trying to grab youtube video data:

http://gdata.youtube./feeds/api/videos/gzDS-Kfd5XQ?v=2&alt=json-in-script&callback=youtubeFeedCallback

The javascript callback function that will be called is youtubeFeedCallback and it contains only one argument when called.

As of now the function would be something like this,

function youtubFeedCallback(response) {
...
}

What I would like to be able to do is pass a second argument like this,

function youtubeFeedCallback(response, divId) {
...
}

Is this possible to do. I've tried looking everywhere online and couldn't find anything. Thanks!

• javascript
• youtube
• jsonp

Share Improve this question Follow edited Jul 2, 2011 at 5:09 mu is too short 435k7171 gold badges859859 silver badges818818 bronze badges asked Jul 2, 2011 at 4:49 Jenn Jenn 2111 silver badge22 bronze badges 1

• The Youtube URL call is being done with an inline script tag. I'm making multiple video entry calls and need to pass a divId so I know which div element to use to put in the returned json video data. I would really like to pass in the divId at the time that the youtube URL is being called. – Jenn Commented Jul 2, 2011 at 17:01

Add a ment  | 

3 Answers 3

Sorted by: Reset to default 5

You can't add arguments to the callback function like that. However, you can generate a wrapper function. The JSONP callback function just was to be a function in the default namespace, that means that you just need to add a generated function with a known name to the global window object. Step one is to make up a name:

var callback_name = 'youtubeFeedCallback_' + Math.floor(Math.random() * 100000);

In the real world you'd want to wrap that in a loop and check that window[callback_name] isn't already taken; you could use window.hasOwnProperty(callback_name) to check. Once you have a name, you can build a function:

window[callback_name] = function(response) {
    youtubeFeedCallback(response, divId);
};

You'd want to that up a little bit more though:

function jsonp_one_arg(real_callback, arg) {
    // Looping and name collision avoidance is left as an exercise
    // for the reader.
    var callback_name = 'jsonp_callback_' + Math.floor(Math.random() * 100000);
    window[callback_name] = function(response) {
        real_callback(response, arg);
        delete window[callback_name];  // Clean up after ourselves.
    };
    return callback_name;
}

Once you have something like that wired up, you could just call:

jsonp = jsonp_one_arg(youtubeFeedCallback, divId);

And then use the value of jsonp as the callback value in the YouTube URL.

You could build more functions like this to handle longer arguments lists too. Or you could build a general purpose one with arguments and apply.

better way is specify an associated array of divId and videoId like this

var arr = {
    'gzDS-Kfd5XQ': 'divId_1',
    'gwWS-Gasfdw': 'divId_2'
};

and in callback function get your divId by videoId

function youtubFeedCallback(data)
{
    var divId = arr[data.entry.media$group.yt$videoid.$t];
}

When creating a "script" object, you can add attributes to it, and reference them later with document.currentScript. This worked for me but other people may need something more elegant.

function blah(stuff,extraarg){
    cs=document.currentScript;
    console.log(stuff); // stuff is your json output
    console.log(cs.extraarg); // cs.extraarg is your extra arg
}

function thing(extraarg){
    var url='https://....&json_callback=blah';
    var s=document.createElement('script');
    s.src=url;
    s.extraarg=extraarg;
    document.body.appendChild(s);
}