,

Applet- Applet online.
:
======================================== ===================================
package AppletsTutorial;
import java.awt.*;
import javax.swing.*;
public class DemoApplet extends JApplet {

@Override
public void paint(Graphics g) {
super.paint(g);
g.drawString("WOW This really worked", 25, 25);
}
}
======================================== ====================================

HTML :
======================================== ====================================
<html>
<head>
<title>Applet</title>
</head>
<body>
<applet code="DemoApplet.class" width="200" height="300"></applet>
</body>
</html>
======================================== ====================================

FireFox, Explorer Google Chrome , :

NoClassDefFoundError

(Java Plug-in 10.9.2.05
Using JRE version 1.7.0_09-b05 Java HotSpot(TM) Client VM)

.