HTMLMediaElement：mediaKeys 属性
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2019年3月.
HTMLMediaElement.mediaKeys 只读属性返回包含一组密钥的 MediaKeys 对象，元素可在播放期间使用这些密钥对媒体数据进行解密。