PresentationAvailability：value 属性
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
value 属性必须返回上次设置的值。该值由监视可用的演示显示器列表算法更新。
规范
| Specification |
|---|
| Presentation API # dom-presentationavailability-value |