In JavaScript I need to detect if YouTube ad is currently playing, my code is not working for me. This is a single page personal project no need to use YouTube Data API.

   function onPlayerStateChange(event) {
    if (event.data == YT.PlayerState.PLAYING) {
      if (document.querySelector(".video-ads .ad-container, .ytp-ad-player-overlay")) {
        YouTubeAdChannel.postMessage('ad_playing');
      }
    }
  }