YouTube JS API Helper

youtube-api-helper.js

/**
 * @author       Rob W <gwnRob@gmail.com>
 * @website      http://stackoverflow.com/a/7513356/938089
 * @version      20120724
 * @description  Executes function on a framed YouTube video (see website link)
 *               For a full list of possible functions, see:
 *               https://developers.google.com/youtube/js_api_reference
 * @param String frame_id The id of (the div containing) the frame
 * @param String func     Desired function to call, eg. "playVideo"
 *        (Function)      Function to call when the player is ready.
 * @param Array  args     (optional) List of arguments to pass to function func*/
function callPlayer(frame_id, func, args) {
    if (window.jQuery && frame_id instanceof jQuery) frame_id = frame_id.get(0).id;
    var iframe = document.getElementById(frame_id);
    if (iframe && iframe.tagName.toUpperCase() != 'IFRAME') {
        iframe = iframe.getElementsByTagName('iframe')[0];
    }

    // When the player is not ready yet, add the event to a queue
    // Each frame_id is associated with an own queue.
    // Each queue has three possible states:
    //  undefined = uninitialised / array = queue / 0 = ready
    if (!callPlayer.queue) callPlayer.queue = {};
    var queue = callPlayer.queue[frame_id],
        domReady = document.readyState == 'complete';

    if (domReady && !iframe) {
        // DOM is ready and iframe does not exist. Log a message
        window.console && console.log('callPlayer: Frame not found; id=' + frame_id);
        if (queue) clearInterval(queue.poller);
    } else if (func === 'listening') {
        // Sending the "listener" message to the frame, to request status updates
        if (iframe && iframe.contentWindow) {
            func = '{"event":"listening","id":' + JSON.stringify(''+frame_id) + '}';
            iframe.contentWindow.postMessage(func, '*');
        }
    } else if (!domReady || iframe && (!iframe.contentWindow || queue && !queue.ready)) {
        if (!queue) queue = callPlayer.queue[frame_id] = [];
        queue.push([func, args]);
        if (!('poller' in queue)) {
            // keep polling until the document and frame is ready
            queue.poller = setInterval(function() {
                callPlayer(frame_id, 'listening');
            }, 250);
            // Add a global "message" event listener, to catch status updates:
            messageEvent(1, function runOnceReady(e) {
                var tmp = JSON.parse(e.data);
                if (tmp && tmp.id == frame_id && tmp.event == 'onReady') {
                    // YT Player says that they're ready, so mark the player as ready
                    clearInterval(queue.poller);
                    queue.ready = true;
                    messageEvent(0, runOnceReady);
                    // .. and release the queue:
                    while (tmp = queue.shift()) {
                        callPlayer(frame_id, tmp[0], tmp[1]);
                    }
                }
            }, false);
        }
    } else if (iframe && iframe.contentWindow) {
        // When a function is supplied, just call it (like "onYouTubePlayerReady")
        if (func.call) return func();
        // Frame exists, send message
        iframe.contentWindow.postMessage(JSON.stringify({
            "event": "command",
            "func": func,
            "args": args || [],
            "id": frame_id
        }), "*");
    }
    /* IE8 does not support addEventListener... */
    function messageEvent(add, listener) {
        var w3 = add ? window.addEventListener : window.removeEventListener;
        w3 ?
            w3('message', listener, !1)
        :
            (add ? window.attachEvent : window.detachEvent)('onmessage', listener);
    }
}

Any idea what is the command for "unlistening" to the frame events?

function postMessage(frame_id, func, args){

    if (window.jQuery && frame_id instanceof jQuery){ 
            frame_id = frame_id.get(0).id; 
    }

    var iframe = document.getElementById(frame_id);

    if (iframe && iframe.tagName.toUpperCase() != 'IFRAME') {
        iframe = iframe.getElementsByTagName('iframe')[0];
    }

    if(iframe) {
        if(typeof(iframe.contentWindow.postMessage) == "function"){

            // Frame exists, 
            iframe.contentWindow.postMessage(JSON.stringify({
                "event": "command",
                "func": func,
                "args": args || [],
                "id": frame_id
            }), "*");
        }
    }
}

That is the short version

Is there any possibility to add Event-Listeners like onStateChanged or get any values back from the YT-iFrame after calling callPlayer? callPlayerworks great for all methods that invoke any kind of action to the YT-Player (playVideo, pauseVideo, mute, ...)

// how to add listeners (example not working)
callPlayer(iFrame, "onStateChanged", function (e) {
  // do something after the state of the YT-Player has changed
})

// how get get a return value via callPlayer if the method which is called normally returns a value?
callPlayer(iFrame, "getPlayerState")