To view the applet's html source code: Right Click This Page --> View Source and look for <applet> </applet> code.
The applet is invoked with JavaScript through: document.jZebra.applet.append("RAW DATA"); and document.jZebra.applet.print();. For more details, Right Click This Page --> View Source and look for <script> </script> code.
If the applet loads above, you can view it's output by enabling the Java console through Control Panel.