How to show the “Are you sure you want to navigate away from this page?” when changes committed?

Question

Here in stackoverflow, if you started to make changes then you attempt to navigate away from the page, a javascript confirm button shows up and asks: \"Are you sure you want

Answer 1

It can be easily done by setting a ChangeFlag to true, on onChange event of TextArea. Use javascript to show confirm dialog box based on the ChangeFlag value. Discard the form and navigate to requested page if confirm returns true, else do-nothing.