ciao... devo aggiungere un altra select..un terzo radiobutton, ho provato così ma non va:

codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
</head>

<body bgcolor="white" text="black" link="blue" vlink="purple" alink="red">
<form action="provare.asp" method="get" name="modulo" id="modulo">
    <table border="0" width="973">
        <tr>
            <td width="134">
                

Seleziona</p>
            </td>
            <td width="822">
                


                  <input name="abilita" type="radio" onClick="if(this.form.abilita[0].checked){this.form.select_radio_0.disabled=false;this.form.select_radio_1.disabled=true}" value="radiobutton">
                  <select name="select_radio_0" size="1" disabled="disabled" id="select_radio_0">
                    <option value="1" selected>Campo1</option>
                    <option value="2">Campo2</option>
                    <option value="3">Campo3</option>
                    <option value="4">altro</option>
		
                </select>
                  <input name="abilita" type="radio" onClick="if(this.form.abilita[1].checked){this.form.select_radio_1.disabled=false;this.form.select_radio_0.disabled=true}else{alert('errore');}" value="radiobutton">
                  <select name="select_radio_1" size="1" disabled="disabled" id="select_radio_1">
                    <option value="1" selected>Campo1</option>
                    <option value="2">Campo2</option>
                    <option value="3">Campo3</option>
                    <option value="4">altro</option>
                  </select>
                <input name="abilita" type="radio" onClick="if(this.form.abilita[2].checked){this.form.select_radio_2.disabled=false;this.form.select_radio_0.disabled=true;this.form.select_radio_1.disabled=true}else{alert('errore');}" value="radiobutton">
                  <select name="select_radio_2" size="1" disabled="disabled" id="select_radio_2">
                    <option value="1" selected>Campo1</option>
                    <option value="2">Campo2</option>
                    <option value="3">Campo3</option>
                    <option value="4">altro</option>
                  </select>
              </p>
            </td>
        </tr>
        <tr id="riga_y">
            <td width="134"> </td>
            <td width="822"><input type="submit" name="formbutton1"></td>
        </tr>
    </table>
</form>


 </p>
</body>
</html>