TextTrackCueList: length 屬性

值

一個無符號長整型（unsigned long），表示列表中提示的數量。

示例

TextTrack.cues 屬性返回一個 TextTrackCueList，其中包含該特定軌道上的當前提示。呼叫 cues.length 會返回列表中提示的數量。使用下面的 WebVTT 軌道，length 的值為 5。

WEBVTT

first
00:00:00.000 --> 00:00:00.999  line:80%
Hildy!

second
00:00:01.000 --> 00:00:01.499 line:80%
How are you?

third
00:00:01.500 --> 00:00:02.999 line:80%
Tell me, is the ruler of the universe in?

fourth
00:00:03.000 --> 00:00:04.299 line:80%
Yes, they're in - in a bad humor

fifth
00:00:04.300 --> 00:00:06.000 line:80%
Somebody must've stolen the crown jewels

const video = document.getElementById("video");
video.onplay = () => {
  console.log(video.textTracks[0].cues.length); // 5
};

規範

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