form mutabile se radio selezionato

[cavicchiandrea]

<form>
<INPUT TYPE="TEXT" NAME="NOME"><INPUT id="cognome" style="display:none" TYPE="TEXT" NAME="COGNOME">
<input type="radio" name="1" value="prova" onclick="document.getElementById('cognome').style. display='inline';">
<input type="radio" name="1" value="prova2" onclick="document.getElementById('cognome').style. display='none';">
<input type="radio" name="1" value="prova3" onclick="document.getElementById('cognome').style. display='none';">
</form>