Thank you, Rob! Also, I can confirm that your script's working flawlessly under Firefox 50 with Greasemonkey extension! But this solution fails if your work flow includes sending many notes with a lot of links to different people! But, thanks anyway! At least, it's a good fit for my personal use!
There's absolutely no any logic in "You are leaving Evernote" tab feature! This feature is needed on forums where unknown member suggests to go to some links. In this case system could warn that you're leaving the forum and admins are not responsible for contents of those links! In case when you create a note and you paste links into the notes, it's meant that those links are 100% verified by you! You created a note, you found links and you pasted them into the note! Not somebody unknown! That's why "You are leaving Evernote" tab is absolutely useless for Evernote !