Javascript在关闭浏览器窗口时获取重定向警报

I'm trying to get this Javascript to work properly. My intention is, when a user is trying to close the site page to get an alert saying "stay on current page or close" If they hit 'ok' I want it to close, if they hit 'cancel' i want it to redirect to another page. The problem is, when they try to go to another page on the same site, it gives them that popup. I want it to show only when closing, not when leaving the page to another page. I'm not sure if that's possible, I do appreciate your help and comments.I'm trying to get this Javascript to work prope