YouTube iframe API: how do I control a iframe player that’s already in the HTML

Fiddle Links: Source codePreviewSmall version
Update: This small function will only execute code in a single direction. If you want full support (eg event listeners / getters), have a look at Listening for Youtube Event in jQuery

As a result of a deep code analysis, I’ve created a function: function callPlayer requests a function call on any framed YouTube video. See the YouTube Api reference to get a full list of possible function calls. Read the comments at the source code for an explanation.

On 17 may 2012, the code size was doubled in order to take care of the player’s ready state. If you need a compact function which does not deal with the player’s ready state, see

 * @author       Rob W <>
 * @website
 * @version      20120724
 * @description  Executes function on a framed YouTube video (see website link)
 *               For a full list of possible functions, see:
 * @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(;
                if (tmp && == frame_id && tmp.event == 'onReady') {
                    // YT Player says that they're ready, so mark the player as ready
                    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 ( return func();
        // Frame exists, send message
            "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);


callPlayer("whateverID", function() {
    // This function runs once the player is ready ("onYouTubePlayerReady")
    callPlayer("whateverID", "playVideo");
// When the player is not ready yet, the function will be queued.
// When the iframe cannot be found, a message is logged in the console.
callPlayer("whateverID", "playVideo");

Possible questions (& answers):

Q: It doesn’t work!

A: "Doesn’t work" is not a clear description. Do you get any error messages? Please show the relevant code.

Q: I have embedded a YouTube video using <iframe src="" />but the function doesn’t execute any function!

A: You have to add ?enablejsapi=1 at the end of your URL: /embed/vid_id?enablejsapi=1.

Q: I get error message "An invalid or illegal string was specified". Why?

A: The API doesn’t function properly at a local host (file://). Host your (test) page online, or useJSFiddle. Examples: See the links at the top of this answer.

Q: How did you know this?

A: I have spent some time to manually interpret the API’s source. I concluded that I had to use thepostMessage method. To know which arguments to pass, I created a Chrome extension which intercepts messages. The source code for the extension can be downloaded here.

Q: What browsers are supported?

A: Every browser which supports JSON and postMessage.

  • IE 8+
  • Firefox 3.6+ (actually 3.5, but document.readyState was implemented in 3.6)
  • Opera 10.50+
  • Safari 4+
  • Chrome 3+

Related answer / implementation: Fade-in a framed video using jQuery

Full API support: Listening for Youtube Event in jQuery

Revision history
  • 17 may 2012

    Implemented onYouTubePlayerReady: callPlayer('frame_id', function() { ... }).

    Functions are automatically queued when the player is not ready yet.

  • 24 july 2012

    Updated and successully tested in the supported browsers (look ahead).

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