Personally, I don’t like browsers that throw up a warning dialog box when you try to close them with multiple tabs open. But I recently discovered that a lot of people do like this functionality, especially when they have dozens of browser tabs loaded. Unfortunately for those users, Chrome doesn't offer a warning box (even as an advanced option) on Windows.If you want to see a warning before closing Chrome here’s a quick solution. Admittedly, it’s a bit of a hack, but it works.Open the websitePrevent Closeby Germany-based developerMichael Armbruster. This website uses JavaScript to throw up a dialog box that asks you if you’re sure you want to leave that specific website.The idea is to always leave that website tab open in Chrome. Then when you click the big red “X” to close the browser, this site throws up a dialog box asking if you’re sure you want to leave that page. If you clickStaythe browser window will not close, if you clickLeaveChrome shuts down.It’s a neat little trick that uses a method less-than-reputable websites have been using for years. This time around, however, this little piece of JS magic is being usedfor good.To make this as painless as possible, I recommend pinning this website to your browser then moving the tab out of the way. To do that open Prevent Close, and then right-click the tab with your mouse. From the context menu selectPin tab....
see full post hear. http://darotech..com/2016/11/how-to-make-chrome-warn-you-before.html