Hello
When searching about window focus, the window-events tutorial page comes up in web search engine results. Page mentions lost/gainedFocus() which is great but we also have hasFocus() and requestFocus() which is the real deal from what I read.
I believe these focus related functions should be on the tutorial page, even if it's just a single sentence, to ensure all newcomers reading about focus is aware of these two functions.
Here is an example web search showing very old stuff and NOT making clear that these new two functions exist:
I have created a pull request for this.
Thanks