Hi,
APEX 19.1.
When we try to navigate to other page after some changes we get an APEX inbuilt warning message like

We can use apex.page.warnOnUnsavedChanges to change the message
My question is -
1. Can we customise "Leave Site" heading? If yes, how to customise?
2. Where should I put this js apex.page.warnOnUnsavedChanges?
3. Can we have our own small popup instead of browser default?
Please suggest.
Thanks,
Veerendra