On Sat, 16 Feb 2019 03:29:49 -0500, Paul wrote:

Interesting.

Now I can see from how this thread developed,
there are two concepts at work.

1) Only one item on the desktop can have the focus. The focus
implies "capture of keyboard" input as one element. I was prepared
to answer "you cannot cheat on focus". But this isn't your
actual question.

2) I didn't think about this, but tabs within a browser
have foreground and background. Only one tab in a browser
window can be in the foreground. But this is not "focus",
since if Notepad is clicked in Windows and is ready for
input from the keyboard, that is "focus".

The concept in (2) of a foreground tab, is addressed here.

https://developer.mozilla.org/en-US/...Visibility_API

Paul

AFAIK, Chrome introduces a more aggresive way to "optimize" web browser
performance by throttling down or even suspend script executions in non
active tabs.