<html> <head> <title>Device Controller </title> </head> <body> <h1> Device Controller Demo</h1> <table> <tr> <td><img src ="ledon.gif" ></td> <td><img src ="ledoff.gif" ></td> </tr> <tr> <td> <a href="/servlet/DeviceController?button1"> <img src="button.gif"></a> </td> <td> <a href="/servlet/DeviceController?button2"> <img src="button.gif" ></a> </td> </tr> </table> <p>LED 1 is on.</p> <p>LED 2 is off.</p> <p>Click a button to turn an LED on or off.</p> <p>The Web page will update to show the current states of the LEDs.</p> </body> </html> Listing 1. The HTML code for Figure 1ís Web page includes links to images that match the states of the LEDs.