JavaScript for youtube thumbnail overlay

gistfile1.js

(function() {
    var $overlay = $('#image-overlay'),
        // NYAN CAT!!
        youtubeVideoId = 'QH2-TGUlwu4',
        // id of the element the object embed will replace
        playerPlaceholderId = 'video-placeholder',
        // id we want to give to the new <object>
        playerId = 'video-player',
        // shockwave flash object params
        params = {
            allowScriptAccess: 'always',
            wmode: 'transparent'
        },
        // shockwave flash object attributes
        attrs = {
            id: playerId
        },
        // object we'll call playeVideo() on once it is loaded
        playerApi,
        // function YouTube will call when the player is ready
        playerReady,
        // function called when player state changes (play/pause/stop/end/etc)
        playerStateChange;

    // defining the callback fuction to be called when player is on the page
    // and ready to play
    playerReady = function() {
        var $player = $('#' + playerId),
            playerOffsets = $player.offset();
        playerApi = $player[0];
        // scoot the overlay image into place over the swf object embed
        $overlay.css({
            left: playerOffsets.left,
            top: playerOffsets.top
        });
        // on overlay click, hide the overlay and play the video
        $overlay.click(function() {
            $overlay.hide();
            playerApi.playVideo();
        });
        // when video is done playing, put the overlay back
        playerApi.addEventListener('onStateChange', 'onYouTubePlayerStateChange');
    };

    playerStateChange = function(event) {
        if (event === 0) {
            $overlay.show();
        }
    };

    // see http://code.google.com/p/swfobject/wiki/api for details
    // (I don't really care about the details. ;) )
    swfobject.embedSWF(
            // URL of video
            'http://www.youtube.com/v/' + youtubeVideoId + '?enablejsapi=1&playerapiid=ytplayer&version=3&rel=0',
            // id to put the object embed within
            playerPlaceholderId,
            // width
            '500',
            // height
            '500',
            // don't know
            '8',
            // don't care
            null,
            // not sure
            null,
            // params and attrs defined above
            params,
            attrs
    );

    // export global functions youtube expects to call
    window.onYouTubePlayerReady = playerReady;
    window.onYouTubePlayerStateChange = playerStateChange;

})();