Hi experts, how are you all doing? Hope you're all doing great. I'm looking for a way to show a warning message at the time of closing a page.
I'm customizing customer card page. I want to show a warning message 'Do you want to close page without Vat. Registration No.?' at the time of closing customer card page. If a user selects 'Yes' then current card page should be closed but if a user selects 'No' then current card page should not be closed.

Answers will be highly appreciated.