Javascript Radio button to disable form elements fields

If this radio button checked disable form elements under the third radio button
<input name="bill" id="bill"  type="radio"  value="above">Bill me at the above address

If this radio button checked disable form elements under the third radio button
<input name="bill" id="bill" type="radio" value="newbilling" >Bill me at this address:

If the above radio buttons are selected disable form elements below.
<input name="bill" id="bill" type="radio"   value="creditcardpayment" checked >
<input type="text" class="textEntry1" name="billingname" id="billingname"  size="42">
<input type="text" name="billingstreetaddress" id="billingstreetaddress" size="42" maxlength="255" />
<input type="text" name="billingcity"  id="billingcity" size="25" maxlength="64" /