为什么 YouTube iframe 播放器在加载时不调用 onYouTubePlayerReady?

I want to load a YouTube video, then mute, play, pause, and unmute it immediately. In doing this, I hope to present the user with a video that doesn't have a big play button on it, and does have the controls on the bottom. In order to do this, I have the following code:

<script type="text/javascript">
function onYouTubePlayerReady(playerid)
{
    mutePlayPauseUnmute(playerid);
}
function onYouTubePlayerAPIReady(playerid)
{
    mutePlayPauseUnmute(playerid);
}
function onYouTubeIframeAPIReady(playerid)
{
    mutePlayPauseUnmute(playerid)
}
function onPlayerReady(playerid)
{
    mutePlayPauseUnmute(playerid)
}

function mutePlayPauseUnmute(playerid)
{
    var player = document.getElementById(playerid);
    player.mute();
    player.playVideo();
    player.pauseVideo();
    player.unMute();
}
</script>
<iframe id="quotedVideo1" type="text/html" width="246" height="160" src="https://www.youtube.com/embed/NWHfY_lvKIQ?modestbranding=1&rel=0&showinfo=0&autohide=1&iv_load_policy=3&theme=light&enablejsapi=1&playerapiid=quotedVideo1" frameborder="0"> <!-- Magic Comment --> </iframe>

但是，经检查，onYouTubePlayerReady、onYouTubePlayerAPIReady、onYouTubeIframeAPIReady、onPlayerReady 和 mutePlayPauseUnmute 曾经被调用过.我做错了什么? 根据 https://developers.google.com/youtube/js_api_reference#onYouTubePlayerReady 看起来它应该可以工作，但它没有.

var tag = document.createElement('script');
tag.src = o.protocol + "://www.youtube.com/iframe_api";
var firstScriptTag = document.getElementsByTagName('script')[0];
firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

playerid.mute();
playerid.playVideo();
playerid.pauseVideo();
playerid.unMute();