var needsConfirm = false;

            function confirmExit() {
                if(needsConfirm)
                    return "You will lose any unsaved changes!";
            }

            function closeWithoutConfirm() {
                needsConfirm = false;
                window.close();
            }
            
            function FormDataChanged() {
                needsConfirm = true;
            }

            function FormDataReset() {
                needsConfirm = false;
            }
            window.onbeforeunload = confirmExit;