The Page Visibility API assists with identifying if a window is visible to a user. According to specification overviews this assists with identifying:
- If a user has moved to another browser tab
- If a user has minimized the browser window
However, it does not assist with answering the question of whether the current window is visible but obscured e.g. by another window in the foreground.
Focus and Blur events - monitored on the browser window - can identify if the user is no longer interacting but not if it is obscured. There are Stackoverflow responses highlighting its use for detecting "active" and "non-active" window states.
Is there guidance on how to check if a browser window is full or partially obscured by another foreground application.
