codice:
<html>
<body>
<select name="jumpmenu" onchange="window.frames['dest_frame'].location=this.value">
  <option></option>
  <option value="http://www.google.com">GOOGLE</option>
  <option value="http://www.yahoo.com">YAHOO!</option>
  <option value="http://www.msn.com">MSN</option>
</select>
<iframe name="dest_frame" width="400" height="300"></iframe>
</body>
</html>