I can't play youtube chromeless player on chrome extension

问题

I'm newbie at chrome extension. I'm making chrome extension that play youtube chromeless player.

It worked on chrome web browser. But, it isn't working on chrome extension.

I tested local .swf file. That is worked on chrome extension.

I think, chrome extension can't call onYouTubePlayerReady().

So I called window.onYouTubePlayerReady() after swfobject.embedSWF(). But, it isn't worked at ytplayer.loadVideoById("xa8TBfPw3u0", 0); with error message.

The error message was Uncaught TypeError: Object #<HTMLObjectElement> has no method 'loadVideoById'.

Is there a problem in manifest.json? Or in YouTube API? I don't know why isn't working on chrome extension.

popup.html is

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>YouTube Play</title>
    </head>
    <body>
    <table width="1000" height="390">
        <tr>
            <td>
            <div id="videoDiv">
                Loading...
            </div></td>
            <td valign="top">
            <div id="videoInfo">
                <p>
                    Player state: <span id="playerState">--</span>
                </p>
                <p>
                    Current Time: <span id="videoCurrentTime">--:--</span> | Duration: <span id="videoDuration">--:--</span>
                </p>
                <p>
                    Bytes Total: <span id="bytesTotal">--</span> | Start Bytes: <span id="startBytes">--</span> | Bytes Loaded: <span id="bytesLoaded">--</span>
                </p>
                <p>
                    Controls: <input type="button" id="play" value="Play" />
                    <input type="button" id="pause" value="Pause" />
                    <input type="button" id="mute" value="Mute" />
                    <input type="button" id="unmute" value="Unmute" />
                </p>
                <p>
                    <input id="volumeSetting" type="text" size="3" />
                    &nbsp;<input type="button" id="setVolume" value="Set Volume" /> | Volume: <span id="volume">--</span>
                </p>
            </div></td>
        </tr>
    </table>

    <script type="text/javascript" src="jsapi.js"></script>
    <script type="text/javascript" src="my_script.js"></script>
    <script type="text/javascript" src="swfobject.js"></script>
    </body>
</html>

manifest.json is

{
    "manifest_version": 2,
    "name": "YouTube Player",
    "description": "This extension is YouTube Player",
    "version": "1.0",
    "browser_action": {
        "default_icon": "icon.png",
        "default_popup": "popup.html"
    },
    "permissions": ["tabs", "http://*/*", "https://*/*", "background"],
    "content_scripts": [
        {
            "matches": ["http://www.youtube.com/*"],
            "js": ["my_script.js", "swfobject.js", "jsapi.js"]
        }
    ]
}

my_script.js is

/*
* Chromeless player has no controls.
*/

// Update a particular HTML element with a new value
function updateHTML(elmId, value) {
    document.getElementById(elmId).innerHTML = value;
}

// This function is called when an error is thrown by the player
function onPlayerError(errorCode) {
    alert("An error occured of type:" + errorCode);
}

// This function is called when the player changes state
function onPlayerStateChange(newState) {
    updateHTML("playerState", newState);
}

// Display information about the current state of the player
function updatePlayerInfo() {
    // Also check that at least one function exists since when IE unloads the
    // page, it will destroy the SWF before clearing the interval.
    if (ytplayer && ytplayer.getDuration) {
        updateHTML("videoDuration", ytplayer.getDuration());
        updateHTML("videoCurrentTime", ytplayer.getCurrentTime());
        updateHTML("bytesTotal", ytplayer.getVideoBytesTotal());
        updateHTML("startBytes", ytplayer.getVideoStartBytes());
        updateHTML("bytesLoaded", ytplayer.getVideoBytesLoaded());
        updateHTML("volume", ytplayer.getVolume());
    }
}

// Allow the user to set the volume from 0-100
function setVideoVolume() {
    var volume = parseInt(document.getElementById("volumeSetting").value);
    if (isNaN(volume) || volume < 0 || volume > 100) {
        alert("Please enter a valid volume between 0 and 100.");
    } else if (ytplayer) {
        ytplayer.setVolume(volume);
    }
}

function playVideo() {
    if (ytplayer) {
        ytplayer.playVideo();
    }
}

function pauseVideo() {
    if (ytplayer) {
        ytplayer.pauseVideo();
    }
}

function muteVideo() {
    if (ytplayer) {
        ytplayer.mute();
    }
}

function unMuteVideo() {
    if (ytplayer) {
        ytplayer.unMute();
    }
}

// This function is automatically called by the player once it loads
function onYouTubePlayerReady(playerId) {
    ytplayer = document.getElementById("ytPlayer");
    // This causes the updatePlayerInfo function to be called every 250ms to
    // get fresh data from the player
    setInterval(updatePlayerInfo, 250);
    updatePlayerInfo();
    ytplayer.addEventListener("onStateChange", "onPlayerStateChange");
    ytplayer.addEventListener("onError", "onPlayerError");
    //Load an initial video into the player
    ytplayer.loadVideoById("xa8TBfPw3u0", 0);
}

// The "main method" of this sample. Called when someone clicks "Run".
function loadPlayer() {
    // Lets Flash from another domain call JavaScript
    var params = {
        allowScriptAccess : "always"
    };
    // The element id of the Flash embed
    var atts = {
        id : "ytPlayer"
    };
    // All of the magic handled by SWFObject (http://code.google.com/p/swfobject/)
    swfobject.embedSWF("http://www.youtube.com/apiplayer?" + "&enablejsapi=1&playerapiid=ytplayer", "videoDiv", "640", "390", "8", null, null, params, atts);

    //window.onYouTubePlayerReady();

    document.getElementById("play").onclick = playVideo;
    document.getElementById("pause").onclick = pauseVideo;
    document.getElementById("mute").onclick = muteVideo;
    document.getElementById("unmute").onclick = unMuteVideo;
    document.getElementById("setVolume").onclick = setVideoVolume;
}

function _run() {
    loadPlayer();
}

google.setOnLoadCallback(_run);

Please help me.