e se volessi aggiungere un pulsante e far partire il link solo dopo il suo click ?

<select name="menu" class="campiform" onChange="window.location.href=this.options[this.selectedIndex].value;">
<option value="http://www.aurelwireless.com/wireless/uk/codesending.asp" selected>Code Sending</option>
<option value="http://www.aurelwireless.com/wireless/uk/datatransmission.asp">Radio Modem</option>
<option value="http://www.aurelwireless.com/wireless/uk/antennas.asp">Antennas</option>
<option value="http://www.aurelwireless.com/wireless/uk/special.asp">Special</option>
</select>