codice:
<?xml version="1.0" encoding="iso-8859-1"?>

  <!DOCTYPE html 
     PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
      <title>Code Example by DYNAMIC+</title>

      <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
      <meta http-equiv="Content-Language" content="en-us" />

      <script type="text/javascript">
      <!--


      //-->
      </script>

    </head>
    <body>

      <div>
        <form>

          <input type="checkbox" onclick="this.form['sampletext'].disabled = !this.checked;" /> Enable the textbox!

          <input type="text" name="sampletext" disabled="disabled" value="This is a textbox!" />

        </form>
      </div>

    </body>
  </html>