如何檢查多個HTML5視頻的音頻

Question

我正在嘗試檢查多個視頻是否有音頻，例如： https : //jsfiddle.net/hrd4a0c3/

但這只會檢查一個視頻，我希望它能檢查多個視頻。

document.getElementById("myVideo").addEventListener("loadeddata", function() {
  if (typeof this.webkitAudioDecodedByteCount || this.mozHasAudio || this.audioTracks !== "undefined") {
    if (this.webkitAudioDecodedByteCount > 0 || this.mozHasAudio || this.audioTracks && this.audioTracks.length)
      this.after("has audio");
    else
      this.after("no audio");
  }
});

Answer 1

我將使用class而不是id ，因為id應該引用一個元素。

<video class='myVideo' autoplay loop muted>
  <source src="https://vtt.tumblr.com/tumblr_ok41s7Iebh1t4fjz0_480.mp4" type="video/mp4">
</video>

<video class='myVideo' autoplay loop muted>
  <source src="https://vtt.tumblr.com/tumblr_ok44bpZZka1t4fjz0_480.mp4" type="video/mp4">
</video>

然后，您可以像這樣使用getElementsByClassName ：

var videos = document.getElementsByClassName("myVideo");

for (i = 0; i < videos.length; i++) {
  videos[i].addEventListener("loadeddata", function() {
    if (typeof this.webkitAudioDecodedByteCount || this.mozHasAudio || this.audioTracks !== "undefined") {
      if (this.webkitAudioDecodedByteCount > 0 || this.mozHasAudio || this.audioTracks && this.audioTracks.length)
        this.after("has audio");
      else
        this.after("no audio");
    }
  });
}

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