Hi, actually our customer, when works with our intranet application, they want to open for a while an other application from desktop, they sometimes close the browser with the 'x' (just to see the desktop and launch some program), after that, they don't find any more the browser with our app to continue their work... (obviously !) ..I want only to put an alert on 'x' pressing in order to advise because some of them they think that our app is not compatible with that program... (public administration users... no comments
...for now we decide that we cannot do that. But anyway, many thanks for responding...
P.S. Paul, in this case, X is close the browser... "usually" can remain "usually" and not "always"