javascript - 如何防止使用javascript再次调用函数？

Question

我正在使用 youtube iframe api 来检测视频何时开始播放，有时状态会更改为缓冲然后再次播放，因此 myFunction 在每个 session 中执行多次，如何我让它只运行一次吗？

if (event.data == YT.PlayerState.PLAYING) {
    playing = true;
    player.mute();
    player.setPlaybackQuality('small');

    function myFunction() {
        setTimeout(function(){
            var videoData = player.getVideoData();
            var video_id = videoData['video_id'];
            const Http = new XMLHttpRequest();
            const url='https://url?viewcounter=' + video_id;
            Http.open("GET", url);
            Http.send();
        }, 3000);
    }
}

Answer 1

使用 bool 标志

var alreadyRun = false;
if (event.data == YT.PlayerState.PLAYING && !alreadyRun) {
            playing = true;
            alreadyRun = true;
            player.mute();
            player.setPlaybackQuality('small');
    function myFunction() {
      setTimeout(function(){
        var videoData = player.getVideoData();
        var video_id = videoData['video_id'];
        const Http = new XMLHttpRequest();
        const url='https://url?viewcounter=' + video_id;
        Http.open("GET", url);
        Http.send();
      }, 3000);
    }
}