W3C Invites Implementations of Page Visibility Level 2

The Web Performance Working Group invites implementation of the Candidate Recommendation of Page Visibility Level 2. The Page Visibility API defines a means to programmatically determine the visibility state of a top level browsing context, and to be notified if the visibility state changes. This specification defines a means to programmatically determine the visibility state of a document. This can aid in the development of resource efficient web applications.