How to handle event when the user closing the browser (Urgent Please)

Question

Hi,
How to handle the event when user closes the browser....
i want to display some alter message when user trying to close the browser...
Please can any one help me how i have to do this...........
Thanks.

Answer 1

Finally got this working. You cannot use the stop() or destroy methods. By the time they are called all database connections are gone and you will get a null pointer exception.
You will have to use the onBeforeUnload method in the html file that calls the applet and use JavaScript to call the save method in java which saves the document:
<SCRIPT LANGUAGE="JScript" TYPE="text/javascript">
function Save()
//i call the applets doSave() method from here in which i save all
//changes to the database
top.Tree.document.TestApplet.doSave();
//this will invoke the default IE message for closing the window
//when user clicks on the x in the browser
message = "Your document has been saved."
return message;
window.onbeforeunload=Save;
</SCRIPT>
//the applets doSave()
public void doSave()
//this frame provides user with the message that document is being
//saved
final JFrame frame = new JFrame("Saving");
JPanel contentPane = new JPanel();
JLabel label = new JLabel(" Please wait, saving document...");
frame.getContentPane().add(label,BorderLayout.CENTER);
frame.setSize(250, 100);
frame.setLocation(300, 400);
frame.setResizable(false);
frame.setVisible(true);
frame.addWindowListener(new WindowAdapter()
//the frame is just for user's information, so prevent user from
//closing it or iconifying it.
public void windowClosing(WindowEvent e)
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
public void windowIconified(WindowEvent e)
frame.setState(frame.NORMAL);
//call my saveDocument() method that saves everything to the database.
editorModule.saveDocument();
//System.out.println("finished calling saving document");
//once the saving is done the frame with the message disappears
frame.setVisible(false);
//System.out.println("setting frame to false");
//I also had an exit button in my applet, that would perform the same task, however now with the above onBeforeUnload method, the exit message would appear twice, so had to modify my exit button action performed, so that if the exitbutton was clicked the onbeforeunload method would get passed a null value and not do anything.
private void exitButton_actionPerformed()
if (DEBUG) System.out.println("Calling exit");
doSave();
window.eval("this.onbeforeunload=null;");
window.eval("top.close();");
//continue from here if user cancels the closing of the window
window.eval("this.onbeforeunload=doSave;");
window.eval("top.focus()");
window.eval("document.TestApplet.requestFocus()");
homePanel.requestFocus();
}