Music files not stopping even after closing browser

[rasen58]

Hi, in my JApplet, I play music files when you click on a button. When I close the applet window in eclipse, the sound stops playing.
However, when I run my applet in a browser, the sound continues and keeps on going until the song finishes. I even included destroy() and stop() functions in which I end the music

public class birthday extends JApplet
{
	....
	
	JPanel songBoard;
	JButton song1;
	JButton song2;
	JButton song3;
	JButton song4;
	AudioClip song;
	URL songPath;
	boolean isPlaying = false;
...
public void init()
{
songBoard = new JPanel();
		songBoard.setLayout(new FlowLayout());
		songBoard.setBounds(180, 50, 700, 500);
		songBoard.setOpaque(true);
		song1 = new JButton("In the End");
		song2 = new JButton("What I've Done");
		song3 = new JButton("New Divide");
		song4 = new JButton("Somewhere I Belong");

		
		song1.addActionListener(action);
		song2.addActionListener(action);
		song3.addActionListener(action);
		song4.addActionListener(action);
		songBoard.add(song1);
		songBoard.add(song2);
		songBoard.add(song3);
		songBoard.add(song4);
		
		pane.add(songBoard, new Integer(1)); //a JLayeredPane
...
}
private class ActionListenerClass implements ActionListener
	{

		@Override
		public void actionPerformed(ActionEvent evt) {

			if(evt.getSource() == song1)
			{
				song= getAudioClip(getDocumentBase(), "In The End.wav");
				playSong();
			}
			else if(evt.getSource() == song2)
			{
				song = getAudioClip(getDocumentBase(), "What I've Done.wav");
				playSong();
			}
			else if(evt.getSource() == song3)
			{
				song = getAudioClip(getDocumentBase(), "New Divide.wav");
				playSong();
			}
			else if(evt.getSource() == song4)
			{
				song = getAudioClip(getDocumentBase(), "Somewhere I Belong.wav");
				playSong();
			}
			
		}
		
	}
	
	public void playSong()
	{
		song.play();
		isPlaying = true;
		progress.setValue(50);
		songBoard.setVisible(false);
	}
	
	public void destroy()
	{
		if(isPlaying)
			song.stop();
	}
	public void stop()
	{
		if(isPlaying == true)
			song.stop();
	}