Hola otra vez:
Te preparé un ejemplo:
<html>
<body>
<form action="index.php" method="get" target="_blank" onsubmit="src.value = (d1.disabled) ? d2.value : d1.value; si.disabled = true; d1.disabled = true; d2.disabled = true; return true;" >
<input type="hidden" name="src" />
<table>
<tr>
<td><div align="left">
<input name="si" type="radio" checked value="" onclick="d1.disabled = (this.checked) ? false : true; d2.disabled = (this.checked) ? true : false; src.value = d1.value;">
opcion1
<br>
</div></td>
<td>Listado:<br>
<select name="d1" size="4" class="tdAzul" >
<option value="1">uno</option>
<option value="2">dos</option>
<option value="3">tres</option>
</select> </td></tr>
<tr>
<td><input name="si" type="radio" value="" onclick="d2.disabled = (this.checked) ? false : true; d1.disabled = (this.checked) ? true : false; src.value = d2.value;">
opcion2 </td>
<td><input name="d2" type="text" size="32" disabled ></td>
</tr>
</table>
<input type="submit">
</form>
</body>
</html>
Tendrías que depurarlo...
Saludos
